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Modulating metal-organic frameworks by surface engineering of stearic acid modification for follicular drug delivery and enhanced hair growth promotion

Journal of Nanobiotechnology volume 23, Article number: 118 (2025) Cite this article

Abstract

Cyclodextrin metal-organic frameworks (CD-MOF) as delivery carriers have gained great attention in the biomedical field. However, limited by challenges of moisture-sensitive nature, the design and application of CD-MOF-based hair follicle delivery for androgenic alopecia (AGA) has rarely been explored. We developed the metal-organic frameworks as hair follicle-targeted delivery system (SA-MOF), stearic acid (SA) was used to modify metal-organic frameworks to form a protective hydrophobic layer on the surface and provide the additional hair growth-promoting effect. Cardamonin (CAR), a newly discovered biosafety natural product, was encapsulated in SA-MOF (CAR@SA-MOF) to promote the therapeutic efficacy on AGA. CD-MOF surface-engineered nanoparticles modified by SA avoided the rapid hydration and disintegration of CD-MOF in water, which improved the drug release and follicular deposition of drug. Assisted by the delivery of SA-modified CD-MOF carriers, the drug significantly promoted cell proliferation and migration, achieving the promoting effect on hair follicle differentiation and hair regeneration in testosterone-challenged C57BL/6 mice. Simultaneously, SA modification provided additional promoting effects on human dermal papilla cell proliferation, regulating effect on keratinocyte growth factor, and activating effect of key signaling pathways. The surface engineering design of CD-MOF hair follicle drug delivery based on SA modification exhibits significant potential for the treatment of hair follicle and sebaceous gland-related diseases.

Graphical Abstract

Highlights

Cyclodextrin metal-organic frameworks (CD-MOF) surface-engineered nanoparticles (CAR@SA-MOF) modified by stearic acid (SA) exhibited a promotion effect on hair growth and could be used as a new therapeutic strategy for androgenetic alopecia.

SA-modification avoids the rapid hydration and disintegration of CD-MOF in water, which provides a new strategy for the sustained long-acting release of drugs in the skin and hair follicles.

SA-modified cyclodextrin metal-organic frameworks could increase hair follicle delivery and accumulation under the ratchet effect.

The therapeutic mechanisms of CAR@SA-MOF on androgenetic alopecia involve regulation of growth factors and activation of Wnt/β-catenin, AKT/ERK, and SHH/Gli signaling pathways.

SA-modification provided additional promoting effect on human dermal papilla cell proliferation, regulating effect on keratinocyte growth factor, and activating effect of key signaling pathways.

Introduction

Androgenetic alopecia (AGA), also known as male pattern baldness, is a frequent hair loss disorder characterized by progressive hair follicular miniaturization [1]. The healthy hair growth cycle can be divided into anagen, catagen, and telogen, whereas AGA shows the extension of telogen and the shortening of anagen. At present, it is generally believed that locally increased androgen levels, overexpression of androgen receptor (AR), and genetic factors play significant roles in the pathogenesis of AGA [2,3,4]. Despite the high prevalence of AGA, effective treatment remains challenging. Limited by the serious adverse reactions faced by clinical first-line drugs such as minoxidil and finasteride [5,6,7], new options are urgently needed to provide more effective and safe treatments of AGA, and several researchers have focused on the use of complementary and alternative medicines, such as natural products or traditional herbs [8]. Cardamonin (CAR) is a flavonoid usually isolated from plant species of the family Zingiberaceae. It was demonstrated that CAR has the effect of promoting hair growth [9]. In our previous studies, CAR delivered by liposomal formulation could accelerate the transition of hair follicles to anagen phase and play an anti-androgenic alopecia role [10].

Nanoparticulate systems for hair follicle delivery have proved to provide obvious advantages, including improved skin bioavailability and the stability and safety of drugs, forming a drug reservoir to prolong release and retention [11, 12]. Importantly, natural accumulation of nanoparticles in the follicular openings following a topical application, and the “targeted effect” of drugs in the hair follicle offer promising potential for the effective management of hair follicle disorders such as AGA [13].

Cyclodextrin metal-organic framework (CD-MOF) is a valuable type of nanocarrier built by Stoddart of γ-cyclodextrin (γ-CD) with alkali metal salts [14]. Due to its advantages of chemical versatility, tunable porosity, high drug-adsorption capacity, and good biocompatibility, CD-MOF shows promising applications in drug delivery [15,16,17]. Currently, CD-MOF can be utilized as carriers for targeting specific body sites, and achieving controlled or stimulus-responsed release of drugs [18,19,20]. CD-MOF delivers drugs to the liver, lung, and oral cavity through various routes such as oral administration, injection administration, inhalation administration, and mucosal application. This provides a potential platform for the diagnosis and drug delivery of CD-MOF in a wide range of diseases, including cancer, pulmonary diseases, oral diseases, and ocular diseases [21]. However, the application of CD-MOF in pilosebaceous related diseases has not been explored. Actually, in our previous research, cross-linked CD-MOF was proved as a feasible follicular delivery vehicle for the treatment of AGA [22]. Yet, using CD-MOF directly as drug delivery presents serious challenges as rapidly disintegrates when exposed to humid conditions, particularly maintaining a long-acting and moist environment for the treatment of AGA. Strategies to improve the stability of CD-MOF in water have been actively developed. The cyclodextrin metal-organic framework obtained by cross-linking diphenyl carbonate shows potential application in drug delivery [23]. In addition, surface modification of CD-MOF by cholesterol is an effective method [24].

Stearic acid (SA) is one of the components of oil secreted by skin, and it is also a kind of saturated fatty acid widely distributed in nature. SA was tremendously used in grafting, nanoparticle modification, and hydrophobic enhancement of various systems [25, 26]. It has been demonstrated that free fatty acids like stearic acid are potent 5α-reductase inhibitors and promote hair growth [27]. In this work, a safe and effective hair follicle-targeted delivery system, SA-modified CD-MOF (SA-MOF) was designed. SA was used to modify CD-MOF to form a protective hydrophobic layer on the surface to maintain a stable structure in water and promote follicular penetration, simultaneously providing the additional effect of promoting hair growth. CAR was then encapsulated in SA-MOF to enhance the efficacy in the treatment of AGA by implementing the in vitro study on human dermal papilla cells and the in vivo study in C57BL/6 mice. The surface engineering of CAR@SA-MOF was demonstrated for fabricating follicle delivery carriers of SA and CAR, where the loading of the two active ingredients is realized by physical adsorption and encapsulation.

Materials and methods

Materials

The materials used in this work are listed in Tables S1 ~ S3. Healthy male C57BL/6 mice, 5 weeks old, 7 weeks old, and New Zealand white rabbits were purchased from the Laboratory Animal Center of Shanghai University of Traditional Chinese Medicine (SHTCM), and studies were approved by the Laboratory Animal Ethical and Welfare Committee of SHTCM. (Approval number: PZSHUTCM210723001, PZSHUTCM210926005). Human dermal papilla cells (hDPCs) were provided by Medsyin Co., Ltd (Shanghai, China).

Pre-treatment of skin

The C57BL/6 mice were anesthetized by intraperitoneal injection of 12.5% ethyl carbamate (1 g/kg), and the dorsal hairs were removed by an electric razor. The adhering subcutaneous tissue was removed carefully and the dorsal skin was subsequently washed with saline, and stored at -20 ℃ for further analysis.

Analytical method for determination of CAR

CAR was determined with a high-performance liquid chromatographic instrument (HPLC, Agilent 1260, USA) and the following conditions: a Diamonsil Plus C18 column (250 mm × 4.6 mm, 5 μm), a mobile phase of 0.2% phosphoric acid-methanol (25: 75, v/v) at a flow rate of 1 mL/min, the detection wavelength of 343 nm, and the column temperature at 30 ℃.

Preparation of nanoformulations

CD-MOF: 1.62 g of γ-CD was mixed with 0.56 g of potassium hydroxide in 50 mL water solution. The solution was filtered with a 0.45 μm filter membrane, and was mixed with 30 mL of methanol, sealed and heated at 50 °C until clear. An equal volume of PEG20,000 methanol solution (16 mg/mL) was added, and the solution was incubated in an ice bath overnight. The precipitates were washed twice with ethanol and dichloromethane and dried in vacuum at 40 °C for 12 h to obtain CD-MOF.

SA-MOF: 30 mg of CD-MOF and 4 mg of SA were weighed, dissolved in 1 mL of 1, 4-dioxane, and stirred at 400 rpm for 24 h at 40 °C. After reaction completion, the reaction mixture was centrifuged at 7853×g, washed with ethanol and pure water, and dried under vacuum at 40 °C for 12 h to obtain SA-MOF.

CAR@MOF: CD-MOF powder (80 mg) was dispersed in 1 mL CAR 1, 4-dioxane solution (4 mg/mL), heated to 40 °C, stirred at 400 rpm for 4 h, and centrifuged at 7853×g. The resulting CAR@MOF was washed twice with ethanol and dried in vacuum at 40 °C for 12 h.

CAR@SA-MOF: 45 mg of CAR and 80 mg of CD-MOF were weighed, and dissolved in 1 mL 1, 4-dioxane, stirred at 400 rpm for 2 h at 40 °C, and then 40 mg of SA was added, and the solution was stirred at 400 rpm for 12 h at 40 °C, centrifuged at 7853×g to obtain CAR@SA-MOF. The precipitates were thoroughly washed with ethanol and pure water to remove unreacted SA and CAR, and dried in vacuum at 40 °C for 12 h.

In addition, CAR was respectively replaced with Coumarin 6 (C6) ethanol solution (4 mg/mL) and an aggregation-caused quenching probe (P4) ethanol solution (50 µg/mL) to prepare C6-labeled SA-MOF (C6@SA-MOF) and P4-labeled SA-MOF (P4@SA-MOF).

Characterization of CAR@SA-MOF

The size distribution was detected by the dynamic light scattering method with a Zetasizer Nano ZS90 instrument (Malvern Panalytical Ltd., Malvern, U.K.). Each experiment was carried out in triplicate at 25 °C.

Drug loading (DL) was determined as follows: CAR in CAR@SA-MOF was fully extracted by ethanol, centrifuged at 7853×g for 10 min, and CAR in the supernatant was determined and drug loading was calculated.

To measure the wetting angles of CD-MOF and SA-MOF, the sample powder to be tested was compressed to the tablet, and water droplets were dropped vertically on the tablet surface, and then measured with an OCA20 optical contact angle meter (DataPhysics Instruments GmbH, Filderstadt, Germany) over time.

The morphology of CD-MOF and SA-MOF was observed by scanning electron microscopy (SEM, Quanta FEG 250, FEI Co., Hillsboro, OR, USA).

Nitrogen adsorption-desorption isotherm at -196 °C (77 K) was measured with a gas sorption analyzer (Autosorb-iQ, Quantachrome). Appropriate amounts of samples were added to the sample tubes and degassed under vacuum (10− 5 Torr) at 60 °C for 12 h. The results were analyzed using the ASiQwin software (version 3.01).

Powder X-ray diffraction (PXRD) patterns of samples to be tested were measured using a D8 Advance X-ray diffractometer (Bruker Corp., Karlsruhe, Germany) with CuKα radiatio (λ = 1.54056 Å) at the tube voltage of 40 kV and current of 40 mA, scanned from 3°~40° at the speed of 0.1 s/step over a diffraction angle of 2θ.

Crude CAR, CD-MOF, SA-MOF, CAR-MOF, CAR@SA-MOF, and the physical mixtures were dried as samples. The Fourier-transform infrared spectroscopy (FT-IR) was determined in the range 400 ~ 4000 cm− 1 by a Nicolet Avatar 330 FT-IR instrument (Thermo Nicolet Corp., Madison, WI, USA).

In vitro release

Free CAR, CAR@MOF, and CAR@SA-MOF were dispersed in phosphate buffer saline (PBS), placed in a dialysis bag (molecular weight cutoff of 14 kDa), and immersed in a PBS-based release medium (pH 6.5 and pH 7.4, respectively) containing 20% (v/v) ethanol and 5% (w/v) Tween-80 to meet the sink condition, stirred at 100 rpm and a constant temperature of 37 °C, sampled at a predetermined time, and supplemented with an equal volume of fresh release medium preheated to 37 °C. Every experiment was performed in triplicate.

In vitro cell experiments

Cell viability assays

hDPCs were cultured under standard conditions (5% CO2, 37 ℃) in Dulbecco’s modified Eagle’s medium (DMEM, high glucose) supplemented with 10% fetal bovine serum and 1% penicillin/streptomycin. Cells (2 × 104 cells/well) were inoculated into 96-well plates and incubated for 12 h. To evaluate the promotion effect of this nanocarrier on cell viability, cells were incubated with free CAR, CAR@MOF, and CAR@SA-MOF (drug concentration: 0.025, 0.050, 0.100, 0.250, 0.500, 0.800, 1.000 µg/mL) for 24 h respectively. Additionally, cells were treated with SA-MOF (1, 2, 5, 10, 20, 50, 100, 200 µg/mL) for 24 h to confirm the biocompatibility of test preparations. Then, the cells of each well were washed with PBS and incubated with Cell Counting Kit-8 reagent for 2.5 h. Optical density (OD) values were determined with a microplate reader at a wavelength of 450 nm and cell viability was calculated according to Eq. (1).

$$\begin{aligned}&\:Cell\:viability\:(\%)\\&=\frac{{OD}_{preparation}-{OD}_{blank}}{{OD}_{control}-{OD}_{blank}}\times\:100\end{aligned}$$
(1)

where ODpreparation, ODcontrol, and ODblank refer to the absorbances of the cells in the test preparation-treated group, cells incubated in drug-free media, and the cell-free group, respectively. Each experiment was performed in triplicate.

Cell uptake

hDPCs were seeded in 6-well plates at a density of 5 × 105 cells/well for 24 h, and then the cells were incubated with a fresh medium containing free C6 and C6-labeled SA-MOF (2 µg/mL) for 2 h. The collected cells were washed with cold PBS three times and then measured the fluorescence intensity of each group using flow cytometry (Becton, Dickinson, and Co., NJ, USA). Each experiment was performed in triplicate.

To observe the distribution of nanoparticles in the cells, hDPCs were seeded in confocal laser scanning microscopy (CLSM) special petri dish at 3 × 105 cells/well, incubated for 24 h, subsequently treated with 2 µg/mL of free C6 or C6@SA-MOF. Cells were incubated with 50 nM of Lyso-Tracker Red solution for 90 min, washed with cold PBS for 2 times, then fixed with 4% paraformaldehyde for 15 min, stained with Hoechst 33,342 solution for 5 min, and quickly imaged under a TCSSP8 CLSM (Leica Microsystems Inc., IL, USA). The excitation (Ex) and emission (Em) parameters were: DAPI Ex 415 nm/Em 485 nm, C6 Ex 498 nm/Em 568 nm, and LysoTracker Red Ex 562 nm/Em 632 nm.

hDPCs were cultured in 6-well plates at a density of 5 × 105 cells/well for 24 h. Next, the cells were pre-treated with FBS-free medium consisting of different inhibitors, sodium azide (10 mM), nystatin (5 µg/mL), and chlorpromazine (10 µg/mL) respectively for 1 h, and then cells washed with cold PBS and incubated with C6@SA-MOF (2 µg/mL) for 2 h. The mean fluorescence intensity was measured by a flow cytometer. Each experiment was performed in triplicate.

Cell migration

hDPCs were seeded at a density of 1 × 106 cells/well in 6-well plates and cultured for 24 h. Cells were scratched and then treated with test groups (drug concentration: 0.1, 0.5, 1.0 µg/mL) for 24 h. The cell migration into wound healing area was monitored at 0 h and 24 h, with an inverted microscope (DMi1, Leica Microsystems Inc., IL, Germany). The cell migration rate was calculated according to Eq. (2).

$$\begin{aligned}&\:Cell\:migration\:rate\:(\%)\\&=\frac{{Wound\:area}_{0\:h}-{Wound\:area}_{24\:h}}{{Wound\:area}_{0\:h}}\times\:100\end{aligned}$$
(2)

Where Wound area0 h and Wound area24 h respectively refer to the cell wound area analyzed by Image J software at 0 h and 24 h. Each experiment was performed in triplicate.

In vitro skin permeation and in vivo deposition studies

In vitro transdermal permeation

A piece of skin was fixed in a Franz transdermal diffusion instrument (Shanghai Huanghai Pharmaceutical Inspection Instrument Co., Ltd., Shanghai, China) with the cross-sectional area of the Franz diffusion cell of 2.8 cm2 and the receptor compartment volume of 12 mL. The stratum corneum layer was faced toward the supply cell, with PBS (pH 7.4) containing Tween-80 (5%, w/v) and ethanol solution (20%, v/v) as the receiving medium under constant agitation of magnetic stirring at 300 rpm and constant temperature of 32 ± 0.5 °C. The same dose of CAR preparation was added to the supply cell. Then, samples were withdrawn at predetermined time intervals, while an equal volume of fresh receiving medium preheated to 32 °C was added to maintain the sink condition. The cumulative amounts of drug permeated through skins were assayed and calculated using HPLC. Each experiment was performed in triplicate.

After 24 h of ex-vivo transdermal delivery, the drug accumulation in the stratum corneum (SC) and the hair follicles (HF) were determined with the Tape-stripping (TS) method and Cyanoacrylate biopsy (CB) method [28, 29]. The skin surface in each diffusion cell was washed with saline to remove any remaining drug and then subjected to TS by application of adhesive Scotch tape 20 times until there were no more attachments on the tape, followed by careful removal to collect the drug deposited in the SC. Following tape stripping, one drop of cyanoacrylate was added, then pressed onto the surface of the stripped skin with light pressure for 15 min. The tape was peeled carefully from the skin and the cured cyanoacrylate with follicular casts was obtained. To quantify the amount of drug from the SC layer and HF, the CAR in the treated tapes was dissolved by 1 mL of methanol and vortexed for 2 h. Additionally, the remaining skin tissues were chopped into small pieces, and homogenized with 1 mL of methanol. After centrifugation at 7853×g for 10 min, the supernatant was collected to determine the un-permeated drug amount before analysis by HPLC. Every experiment was performed in triplicate.

In vivo skin delivery

P4-labeled preparations (P4@Ethanol and P4@SA-MOF) were used to evaluate the skin delivery of nanoformulation in vivo. The five-week-old C57BL/6 mice underwent dorsal hair removal with an electric razor under anesthesia. A cylinder-type chamber with an available area of 1 cm2 was placed with glue on the dorsal skin of the mice. The tested P4 preparations were applied to the skin of different groups of mice in the dark, and removed from the skin at several time points. The skin of mice was dissected and fixed with 4% paraformaldehyde/PBS. Fixed skin was washed with normal saline, embedded in tissue-tek OCT compound, and then frozen in liquid nitrogen. Frozen skin sections of 10 μm thickness were stained with DAPI (10 µg/mL) for 10 min. Images were acquired by AGlient BioTek Cytation 5 (Aent Technologies Inc., Santa Clara, USA). The excitation/emission wavelengths of DAPI and P4 were 358 nm/461 nm and 645 nm/650 nm, respectively. Each experiment was performed in triplicate.

In vivo skin deposition

Shaved dorsal hair skins of C57BL/6 mice were topically applied with P4@SA-MOF on the upper dorsal sides area of 2.25 cm2, and massaged clockwise for 10 min in the index finger. At 2 h post-administration, mice were sacrificed, and the same dose of P4@SA-MOF was administrated on the lower dorsal skin area of 2.25 cm2 without massage. The stripped skin area was treated and imaged by Cytation 5. Each experiment was performed in triplicate.

Anti-AGA efficacy of CAR@SA-MOF in C57BL/6 mice

Establishment and treatment of AGA animal model

C57BL/6 mice were anesthetized with 12.5% ethyl carbamate (1 g/kg) via intraperitoneal injection, and the hair in the dorsal skin area of 6 cm2 was removed by using a shaver after applying a depilatory cream. All C57BL/6 mice were randomly divided into six groups (n = 5). Mice in control group were administered normal salin, TES group was topically applied for 21 days with 0.5% testosterone solution that was prepared in 50% ethanol, and the positive control MXD@Linim group was applied with commercial minoxidil liniment. The tested preparation groups were treated daily with TES for 1 h and followed by topical treatment with crude CAR, CAR@MOF, and CAR@SA-MOF (500 µL per mouse), respectively, and massaged clockwise. Changes in the dorsal skin color of mice were observed and photographed on days 0, 7, 12, 17, and 21 after treatment. The skin was excised, fixed in 4% paraformaldehyde overnight, paraffin embedded routinely, and stained with hematoxylin and eosin (H&E) on day 17. The anagen/telogen ratio (A/T ratio) was determined by observing and calculating the number of hair follicles in anagen phase and telogen phase under optical microscope. At 21th day post-experiment, the dorsal hairs of all groups were shaved and their weight was measured to evaluate hair growth.

Real time-PCR analysis

Total RNA was extracted from dorsal skin tissues using Trizol Reagent. Real-Time PCR reactions were carried out using SYBR green Premix (AppliedBiosystems, Inc., Waltham, Massachusetts, USA) in an ABI Step-One Plus Real-Time PCR system. Real-time PCR was performed under the following conditions for up to 40 cycles: (1) initial activation (95 °C, 5 min), (2) denaturation (95 °C, 15 s), (3) annealing (60 °C, 20 s), and (4) extension (72 °C, 40 s). Table S2 listed the nucleotide sequences of primer pairs used for PCR. Each experiment was performed in triplicate.

Western blot analysis

The expression of total proteins in skin tissues was determined by western blot analysis. The skin tissues were homogenized in ice-cold radioimmunoprecipitation assay (RIPA) buffer and centrifuged at 12,000×g for 5 min at 4 °C prior to collecting the supernatants. Protein samples were subjected to separation 10 ~ 13% SDS-PAGE and transferred to polyvinylidene fluoride membranes by the Trans-Blot Turbo system (Bio-Rad Laboratories, Inc., Hercules, California, USA). Incubation with primary antibodies was performed overnight at 4 °C. After washing the membranes with TBST for 3 times, the secondary antibody incubation was performed for 2 h at RT followed by TBST-washing (list of antibodies was listed in Table S3). The ChemiDoc MP imaging system (Bio-Rad Laboratories, Inc., Hercules, California, USA) was utilized to quantify the protein band intensity. Each experiment was performed in triplicate.

Skin irritation

Skin irritation tests were performed with New Zealand white rabbits, the hairs on the dorsal skin were shaved, only the left side served as control, and the right side was treated. CAR@MOF and CAR@SA-MOF were topically applied to an area of approximately 9 cm2 on the right-side skin once daily for 7 consecutive days. The skin was observed for any visible changes. Dorsal skin samples were dissected, fixed with 10% formalin on day 10, and observed using an optical microscope after H&E staining.

Data analysis

Data are expressed as mean ± standard deviation. The results were analyzed by Student’s t-test for differences between groups and considered statistically significant when P < 0.05.

Results and discussion

Characterization of CAR@SA-MOF

The metal-organic framework with SA surface modification loaded with CAR (CAR@SA-MOF) was prepared by one step-method (Fig. 1A), with an average particle size of 209.8 ± 5.6 nm (Fig. 1B), low polydispersity index (PDI) value (0.140 ± 0.015), and drug loading of 8.54 ± 0.36%. As shown in Fig. 1C, the contact angle of CD-MOF was 33.3°, indicating that CD-MOF was hydrophilic and unstable in water. The contact angle of SA-MOF after modification was 71.3° (Fig. 1D), suggesting that the hydrophobicity of SA-MOF was enhanced and its stability in water was improved. The results of contact angle also confirmed the success of SA-MOF modification. The SEM (Fig. 1E-F) showed that the morphology distribution of CD-MOF and SA-MOF was uniform and cubic crystal structure, suggesting the successful preparation of SA-MOF, and physical adsorption of SA on CD-MOF surface. Interestingly, SA-MOF exhibited a smoother morphology than MOF, with rounder edges, which may be attributed to the fact that SA-MOF underwent washing with pure water during preparation process [24]. More importantly, the particle size distribution was basically consistent with the results of Malvern particle size measurement, which indicated that the modification process has not changed the particle size and appearance of CD-MOF.

Nitrogen adsorption experiments demonstrated that the specific surface area and pore volume of CD-MOF provide a greater possibility for drug molecule delivery to pore systems. The BET surface areas of the CD-MOF were 1075.3 m2/g in our previous study [30], whereas the BET surface areas of SA-MOF were 7.8 m2/g. Additionally, The BET surface areas of the CAR@MOF (19.8 m2/g) and CAR@SA-MOF (4.6 m2/g) decreased significantly compared to CD-MOF. This indicates that the modification of SA is via surface physical adsorption. The N2 adsorption isotherms of SA-MOF and CAR@SA-MOF are shown in Fig. S1. The N2-accessible surface area of CAR@SA-MOF almost decreased to 0 m2/g, indicating that there was nearly no residual porosity remaining in the SA-MOF after CAR loading. Meanwhile, the encapsulation of CAR caused a dramatic reduction in the pore volumes of the CD-MOF pores of 1.7 nm in diameter (Table. S4). It has been documented that biomacromolecules and drugs with larger dimensions were successfully encapsulated by CD-MOF [31, 32]. For small molecule drug encapsulation, such as cardamomin (a molecular weight of 270.28), the pores and structure of CD-MOF provide sufficient space for the inclusion of drug. These results further indicated that CAR was successfully encapsulated in the pores of CD-MOF.

According to the PXRD pattern (Fig. 1G), CD-MOF had significant diffraction peaks at 4.1°, 5.66°, 6.95°, 13.5° and 16.63°. The SA-MOF modified with SA still maintained the above characteristic peaks. The PXRD pattern also revealed the crystal properties of CAR. The crude drug existed in stable crystal form, with well-resolved diffraction peaks at 6.70°, 8.61°, 13.42°, 20.03°, and 25.23°. However, the above characteristic diffraction peaks did not appear in CAR@SA-CDF after drug loading, suggesting that CAR was encapsulated at molecular level and existed in the amorphous form of SA-MOF.

The successful modification of SA-MOF and the complete inclusion of the drug were further verified by FT-IR (Fig. 1H). CD-MOF exhibited stretching vibration peak at 3000 ~ 3600 cm− 1 (-OH), 2800 ~ 3000 cm− 1 (-CH-, -CH2-), and 1000 ~ 1300 cm− 1 (C-O-C). The distinctive peaks of SA at the asymmetric stretching vibration peak of 2850 cm− 1 and symmetrical stretching vibration of 2910 cm− 1 were attributed to -CH2 groups, and another peak at 1704.21 cm− 1 was related to the carb-based stretching vibration peak [33, 34]. In the infrared spectra of SA-MOF, both the spectral characteristic peak of CD-MOF and the stretching vibration peak (CH2) of SA were present. Nevertheless, the presence of the peak at approximately 1720 cm− 1 in SA-MOF indicated the potential formation of ester bonds between the carboxyl group and hydroxyl groups. It confirmed that SA was successfully connected with the hydroxyl group in CD-MOF. The infrared spectrum of CAR showed that the characteristic absorption peak was consistent with the literature, and a strong and sharp vibration band was displayed at 3151.81 cm− 1, which was the O-H stretching vibration absorption peak. 2932 cm− 1, 1627.41 cm− 1 and 1541.10 cm− 1 indicated the presence of peaks of CH2, C = O and CH = CH, respectively [35]. These remarkable characteristic functional groups indicated the presence of CAR, a kind of chalcone. The absorption peaks above in CAR@SA-MOF disappeared after drug loading, suggesting that the CAR was completely packed into the channel of the SA-MOF. These findings suggest the loading of SA and CAR is realized by physical adsorption and encapsulation.

In vitro release

In this study, CAR@SA-MOF was designed as a vehicle for hair follicle-targeted delivery, we mainly focused on the drug release behavior within hair follicles. Therefore, PBS with pH 6.5 and pH 7.4 were selected as the release medium to simulate the slightly acidic environment on the superficial hair follicle and the neutral pH value in the deep hair follicle [36, 37]. The drug release of CAR from crude drugs, CAR@MOF, and CAR@SA-MOF in comparison with the one encapsulated after 96 h were 46.61 ± 4.07%, 85.08 ± 3.65% and 77.59 ± 6.02% in pH 6.5 medium (Fig. 1I), 55.65 ± 2.03%, 83.86 ± 4.17% and 61.13 ± 4.38% in pH 7.4 medium (Fig. 1J), respectively. Notably, the crude CAR was limited by poor water solubility, and the release of CAR after 96 h was less than 50%. The drugs contained in CD-MOF pores will form nanoclusters when they meet water, thus improving the solubility and dissolution rate of drugs [38,39,40,41]. Therefore, the release rates of CAR@MOF and CAR@SA-MOF were significantly higher than those of the crude drug CAR (P < 0.01). Compared with CAR@MOF, CAR@SA-MOF exhibited a certain sustained release effect. The release of CAR@SA-MOF groups was slightly slower than that of CAR@MOF, which is attributed to the hydrophobic property of the surface-modified SA, SA layer avoids the rapid hydration and release of CD-MOF in water, and improves the stability of CD-MOF in water. It provided a new strategy for the sustained long-acting release of drugs in the skin and hair follicles. We found that SA-MOF exhibited faster release rates in slightly acidic release media (pH 6.5) compared to physiological media (pH 7.4). This may be attributed to the fact that CD-MOFs prepared by potassium ions are alkaline and more easily neutralized under acidic conditions, and the addition of SA may form potassium stearate, playing the role of surfactants which promote drug release. Therefore, the faster release of SA-MOF-based carriers is observed in acidic environments, indicating that drug tends to release relatively rapidly in pilosebaceous orifice and release slowly in deeper regions, distribute uniformly along the entire hair follicle.

Fig. 1
figure 1

Synthesis and characterization of CAR@SA-MOF. (A) Synthesis of CAR@SA-MOF; (B) Scatter plots of particle size distribution; The water contact angle measurement of (C) CD-MOF and (D) SA-MOF; SEM images of (E) CD-MOF and (F) SA-MOF; (G) PXRD patterns and (H) FTIR spectra; In vitro release profiles of CAR, CAR@MOF and CAR@SA-MOF at (I) pH 6.5 and (J) pH 7.4

Full size image

Cell uptake

Free C6 easily partitions into the lipid membrane and subsequently diffuses into cells. Due to its highly hydrophobic nature, it accumulates significantly within the cells [42]. As shown in Fig. 2A, the cells in the C6@SA-MOF group exhibited higher fluorescence intensity than the C6@MOF group (P < 0.01), suggesting that the presence of SA can promote the cellular uptake of the drug [43, 44]. Post-incubation with the coumarin 6 (C6)-labeled preparation showed that green fluorescence of C6 was mainly distributed in the cytoplasm, and no signal was observed in nucleus with blue fluorescence (Fig. 2B). Additionally, the green fluorescence signals of C6 overlapped with red fluorescence from LysoTracker Red, indicating that SA-MOF could be effectively captured by lysosomes [45].

To understand the endocytosis pathway of SA-MOF, several specific endocytosis inhibitors including sodium azide, nystatin, and chlorpromazine were investigated. Sodium azide is commonly used as an inhibitor of cellular oxidative respiration. It works by blocking cytochrome oxidase, an enzyme essential for the synthesis of cellular adenosine triphosphate (ATP). By inhibiting this enzyme, sodium azide effectively disrupts ATP production in cells [46]. Nystatin inhibits caveolae-mediated endocytosis via interaction with cholesterol (a process involving small invaginations in the cell membrane called caveolae) [47]. Chlorpromazine is used to inhibit clathrin-mediated endocytosis pathway [48]. The relative cellular uptake rate of SA-MOF showed a significant decrease in the presence of sodium azide (85.57%), nystatin (95.63%), and chlorpromazine (62.49%) as compared with control (P < 0.01) (Fig. 2D). Importantly, the cellular uptake efficiency of MOF was not found to be significantly inhibited by chlorpromazine compared to SA-MOF. This can be attributed to the fact that SA can enhance membrane affinity and greatly improve cell uptake of complexes mediated by clathrin and caveolin [49]. Therefore, the cellular uptake mechanism of SA-MOF is strongly associated with energy-dependent active transport and endocytosis, with a particular emphasis on the clathrin-mediated pathway that directs it towards acidic lysosomal compartments.

Cell proliferation and migration

SA-MOF did not show an obvious cytotoxic effect on hDPCs, and the cell viability values were all higher than 98% at concentrations ranging from 1 to 200 µg/mL (Fig. S2). As shown in Fig. 2E, free CAR promoted cell proliferation within the range of 0.025 ~ 1.000 µg/mL, and exhibited the strongest promotion effect under 0.8 µg/mL concentration (142.49 ± 5.47%). At concentrations ranging from 0.025 to 0.800 µg/mL, the cell viabilities in the CAR@MOF group were significantly elevated compared to those in the free CAR group. Notably, within the concentration range of 0.025 to 0.500 µg/mL, CAR@SA-MOF significantly enhanced the growth of hDPCs compared to the free CAR group, suggesting an increased drug uptake when delivered via CD-MOF and SA-MOF, which in turn led to a more robust promotion of cell proliferation. Furthermore, within the concentration range of 0.025 to 0.500 µg/mL, the cell viability of the CAR@SA-MOF group was markedly higher than that of the CAR@MOF group, indicating an additional stimulatory effect of SA on hDPCs proliferation.

The scratch wound healing migration assay demonstrated that CAR possesses the ability to facilitate the repair and healing of damaged skin and promote hair follicle development. Specifically, when compared to the control group, the scratch healing rates of the tested groups at drug concentrations of 0.1, 0.5, and 1 µg/mL exhibited significant increases after 24 h. Notably, the highest cell migration rate was observed in the CAR@SA-MOF group at a concentration of 0.1 µg/mL, with a rate of 58.55 ± 1.93%, which was statistically significant (P < 0.01) compared to the CAR@MOF group, which had a rate of 45.64 ± 2.48%. Additionally, the cell migration rate of the CAR@SA-MOF group was significantly higher than that of the MXD groups at concentrations of 0.5 and 1 µg/mL (P < 0.05). These findings suggest that CAR@SA-MOF can effectively promote wound healing, cell proliferation, and hair follicle development, as illustrated in Fig. 2F and G.

Fig. 2
figure 2

In vitro cell experiments. (A) hDPCs uptake of free coumarin 6 and coumarin 6-labeled SA-MOF (C6@SA-MOF); (B) hDPCs uptake and colocalization of free coumarin 6 and C6@SA-MOF, imaged by CLSM; hDPCs uptake of C6@MOF (C) and C6@SA-MOF (D) treated with Sodium azide, Nystatin, and Chlorpromazine; (E) hDPCs viability assessed by CCK-8 assay; (F) Effect of free CAR and MXD, CAR@MOF, and CAR@SA-MOF on the migration of hDPCs; (G) hDPCs wound fields were observed with microscope at 0 h and 24 h. (*P < 0.05, **P < 0.01, ***P < 0.001, n = 3)

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Transdermal permeation

Restricted by its inadequate water solubility, the CAR aqueous dispersion group (CAR) exhibited the poorest transdermal penetration among the evaluated groups (Fig. 3A-C). Conversely, the nanoformulation groups demonstrated a substantial enhancement in transdermal drug delivery. Specifically, the cumulative transdermal amount of CAR from the CAR@SA-MOF group surpassed that of the CAR aqueous dispersion group at every experimental time point (Fig. 3A, P < 0.01). Notably, the percutaneous permeation rate of CAR@SA-MOF was significantly elevated compared to the CAR aqueous dispersion (Fig. 3B, P < 0.01). When compared to free CAR, the retention of CAR@SA-MOF within hair follicles was an impressive 26.87 times higher (Fig. 3C). These findings indicate that CAR@SA-MOF can enhance the skin deposition and follicular absorption of drugs.

In this study, a near-infrared fluorescence probe named P4, exhibiting an agglomeration quenching effect, was encapsulated within SA-MOF to track transdermal delivery. The P4 probe, when embedded within the nanocarrier, is capable of emitting a robust fluorescence signal. However, upon its release into the water, the probe spontaneously quenches and completely diminishes any interference from free probes [50, 51]. Figure 3D displayed the vertical sections of skin treated with P4@SA-MOF, capturing intact hair follicles with the hair shafts appearing as dark black on the slide. The blue fluorescence signal signifies the nucleus of dermal cells stained with DAPI, while the red fluorescence signal highlights the skin penetration and accumulation of P4@SA-MOF. Following 4 h of administration, red fluorescence was observed in both the hair follicles and the dermis for P4@SA-MOF. Notably, the intensity of the red fluorescence in the skin gradually increased with longer administration times, indicating that SA-MOF possesses exceptional follicular deposition and dermal permeation capabilities.

It was hypothesized that the ratchet effect, induced by a massage with radial movement frequency of hair, could enhance the penetration of nanoparticles into hair follicles [52, 53]. To explore the impact of this ratchet effect on the transdermal penetration of SA-MOF, a massage application was employed to simulate hair motion and mimic the ratchet effect. A comparison was made between skin treated with and without massage during the application process. As illustrated in Fig. 3E, the red fluorescent signals in the follicular region were significantly diminished when the massage was discontinued. This observation suggests that, under the influence of massage, SA-MOF can effectively penetrate the skin barrier through hair follicles. Furthermore, the ratchet effect resulting from high-frequency hair movement emerges as a pivotal mechanism facilitating follicular delivery of SA-MOF.

Fig. 3
figure 3

In vitro transdermal and dermal delivery of free CAR and CAR@SA-MOF in the skin of topical administration. (A) Cumulative transdermal permeation in mice skin; (B) Transdermal fux in mice skin; (C) The retained amounts in the stratum corneum (SC), hair follicles (HF), and skin layers rest (Skin Rest) of mice skin (**P < 0.01, ***P < 0.001; n = 3); (D) In vivo skin permeation of P4@SA-MOF imaged by Cytation5 after 2, 4, 8, and 12 h (The slides were stained with DAPI, scale bar = 200 μm); (E) Cytation5 images obtained after in vivo application of P4@Ethanol Sulotion and P4@SA-MOF for 2 h. (The mice were treated with P4-labeled preparations in upper dorsal skin area with massage and in lower dorsal skin area without massage; the slides were stained with DAPI, scale bar = 200 μm)

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Anti-AGA efficacy of CAR@SA-MOF in C57BL/6 mice

7-week-old C57BL/6 mice, at the initial stage of the telogen phase of their hair follicles, were utilized as animal models to assess the capacity of the test preparation to promote the anagen phase in vivo, as depicted in Fig. 4A. Furthermore, testosterone was concurrently administered to these mice, as it can disrupt the transition of hair follicles from the anagen to the telogen phase, thereby mimicking the perturbations in testosterone levels observed in AGA.

In Fig. 4B, it is evident that, on the 12th day of administration, the skin of the mice in the control group was predominantly covered with hair, whereas the skin pigmentation of the mice in the TES group turned black. Histological analysis, presented in Fig. 4C, further revealed that, on the 17th day of administration, the majority of hair follicles in the control group were located in the dermis and deep subcutis. Conversely, in the TES group, only a limited number of hair follicles had formed and had entered the telogen phase. Notably, the hair growth time in the TES group was markedly delayed, and the hair coverage rate was significantly lower compared to the control group. This implies that testosterone treatment significantly impeded hair regeneration and delayed the transition to the growth phase in the AGA mice model.

The test preparations exhibited promising potential in promoting hair regeneration. When compared to the TES group, the dorsal skin of the mice in these groups was nearly fully covered by hair shafts by day 21, with a notable increase in the regenerated hair weight, as illustrated in Fig. 4D. Topical application of these test preparations significantly accelerated the transition of hair follicles into the anagen phase, resulting in a significantly higher anagen/telogen phase ratio (A/T) in the test preparation group compared to the TES group, as shown in Fig. 4E. Furthermore, in comparison to CAR@MOF, the CAR@SA-MOF group demonstrated a shorter hair growth duration, higher hair coverage, and greater regenerated hair weight, rivaling even the performance of the positive control group, MXD@Linim, which is a commercially available minoxidil tincture. These results indicated the beneficial role of SA in enhancing hair regeneration in AGA mice, further confirming the efficient delivery of hair follicles by SA-MOF.

It has been definitively established that the growth factors secreted by hDPCs actively participate in the regulatory mechanisms underlying hair follicle development and hold a pivotal position in promoting the proliferation of hair follicle epithelial cells [54, 55]. To delve into the effective mechanisms of test preparations on AGA mice, the expression levels of Insulin-like Growth Factor-1 (IGF-1), Vascular Endothelial Growth Factor (VEGF), Keratinocyte Growth Factor (KGF), and Transforming Growth Factor-β (TGF-β) were meticulously assayed using RT-PCR. IGF-1 is one of the most extensively researched genes due to its crucial role in prolonging the anagen phase and facilitating hair shaft differentiation during hair follicle development. VEGF functions as a paracrine factor, enhancing hair follicle growth and dermal papilla cell proliferation by facilitating the nutrient supply to the hair follicle. KGF is well-documented for its indispensable role in regulating the hair cycle, as well as cell proliferation and differentiation. On the other hand, TGF-β proteins have the ability to induce premature catagen in AGA-affected hair follicles and inhibit the growth of adjacent epithelial cells [56, 57].

When compared to the CAR group, the expression of TGF-β in both the CAR@MOF and CAR@SA-MOF groups exhibited a statistically significant decrease (P < 0.05), as illustrated in Fig. 4F. Conversely, the expression of KGF showed a marked increase (P < 0.01), as depicted in Fig. 4I. These findings indicate that CAR-loaded preparations demonstrate notable hair regeneration-promoting effects, characterized by an upregulation of KGF and a downregulation of TGF-β. Furthermore, a significant elevation in the expression levels of IGF-1 and KGF was observed in both the CAR@MOF and CAR@SA-MOF groups compared to the MXD@Linim group (P < 0.05) (Fig. 4G, I). Notably, in skin tissue treated with CAR@SA-MOF, the expression level of KGF was higher than that in the CAR@MOF group, hinting at the regulatory influence of SA on KGF expression.

Fig. 4
figure 4

Effects of test preparations on hair regeneration in testosterone-induced androgenetic alopecia C57BL/6 mice. (A) Schematic diagram of AGA mice model establishment with topical application of testosterone daily for 21 consecutive days and the topical treatment strategies of each group of mice in the established model; (B) The dorsal skins were photographed on days 0, 7, 12, 17, and 21; (C) The dorsal skin tissues of each group were collected on day 17 and subjected to hematoxylin and eosin (H&E) staining; (D) The mean weight of regenerated hair; (E) The anagen/telogen ratio of hair follicles. (#P < 0.05, ##P < 0.01, represent CAR@MOF vs. other groups; *P < 0.05, **P < 0.01, represent CAR@SA-MOF vs. other groups; n = 5); (F) TGF-β, (G) IGF-1, (H) VEGF, and (I) KGF mRNA expression level of mice at day 21. (*P < 0.05, **P < 0.01, n = 3)

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The intricate process of hair formation, proliferation, and differentiation is intricately linked to the regulation of numerous signaling pathways, such as Wnt/β-catenin, protein kinase B (AKT), extracellular regulated protein kinase (ERK), and Sonic hedgehog (SHH). The β-catenin signaling pathway holds a pivotal role in the formation of hair follicles, maintaining and stimulating the regeneration of hair follicle dermal papilla cells, as well as fostering hair stem growth [58, 59]. Meanwhile, the AKT and ERK pathways engage in a diverse array of signal transduction processes that pertain to cell viability, proliferation, and apoptosis. The activation of ERK plays a vital role in the proliferation of hDPCs, while phosphorylated protein kinase B (p-AKT) can induce the nuclear aggregation of β-catenin protein [60]. Furthermore, the activation of SHH/Gli signaling within hair follicles triggers hair growth by fostering the development of dermal papillae and inducing hair follicles in the catagen phase to transition into the anagen phase [61,62,63]. In this work, western blot analysis was conducted to investigate the expression of proteins associated with the Wnt/β-catenin, AKT/ERK, and SHH/Gli signaling pathways.

As illustrated in Fig. 5, the reduced protein levels observed in TES-treated mice were successfully up-regulated through the topical application of the test preparations. Notably, CAR@SA-MOF demonstrated a significantly more potent effect in upregulating β-catenin expression compared to the other test preparations (Fig. 5A). The mice treated with these preparations restored the levels of AKT/ERK signaling-related proteins, particularly p-AKT and p-ERK. Among them, CAR@SA-MOF exhibited a greater inducing effect on protein expression than CAR@MOF (Fig. 5C). Furthermore, mice treated with CAR@SA-MOF showed significant increases in the expression levels of SMO and SHH compared to those treated with CAR@MOF (Fig. 5D). These findings indicate that the incorporation of SA offers a promising strategy for enhancing the regulation of key signaling pathways.

Fig. 5
figure 5

Effects of test preparations on Wnt/β-catenin, AKT/ERK, SHH/Gli signaling pathways in C57BL/6 mice at day 21. (*P < 0.05, **P < 0.01, represent CAR@SA-MOF vs. other groups, n = 3)

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Skin irritation

The continuous administration of CAR@MOF and CAR@SA-MOF to rabbits over a period of 7 days did not elicit any notable erythema or edema in the skin. The skin irritation scores for the two groups were 0.07 and 0.11, respectively. An analysis of H&E staining in Fig. 6B revealed no apparent epidermal damage or inflammation in the skin of rabbits in the drug treatment group. The results of the skin irritation assessment demonstrated that the continuous application of both CAR@MOF and CAR@SA-MOF did not cause significant irritation to rabbit skin, thus preliminarily establishing their biocompatibility with skin.

Fig. 6
figure 6

Skin irritation of CAR@MOF and CAR@SA-MOF on rabbits. (A) The dorsal skins were photographed on days 0, 3, 7, and 10; (B) The dorsal skin tissues were collected on day 10 and subjected to H&E staining. (a: Administration groups; b: Blank groups, n = 4)

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Conclusion

In this work, a novel potential system for follicular drug delivery, metal-organic frameworks modified stearic acid and loaded with cardamonin (CAR@SA-MOF) was constructed for effectively treating AGA. CAR@SA-MOF improved the drug release and follicular delivery performance, while also developing biocompatibility with skin. This currently developed drug delivery system enhanced the therapeutic effects of the drug in treating AGA, which has been achieved in vitro and in vivo experiments. CAR@SA-MOF contributed to enhanced viability of hDPC and uptake of drugs, improved hair follicle differentiation, and hair regeneration in the C57BL/6 mice of AGA. The therapeutic mechanisms of CAR involve regulation of growth factors including IGF-1, VEGF, and TGF-β. Importantly, SA played a synergistic role in regulating KGF and activating the Wnt/β-catenin, AKT/ERK, and SHH/Gli signaling pathways. We have confirmed that the surface engineering design of SA-MOF provided a promising strategy for the development of an effective follicular delivery carrier for the treatment of pilosebaceous-related diseases.

Data availability

No datasets were generated or analysed during the current study.

Abbreviations

AGA:

Androgenetic alopecia

AR:

Androgen receptor

A/T ratio:

Anagen/telogen ratio

CAR:

Cardamonin

CB:

Cyanoacrylate biopsy

CD-MOF:

Metal-organic framework

CLSM:

Confocal laser scanning microscopy

C6:

Coumarin 6

DHT:

Dihydrotestosterone

DL:

Drug loading

ERK:

Extracellular regulated protein kinases

FDA:

The U.S. Food and Drug Administration

FT-IR:

Fourier-transform infrared spectra

hDPCs:

Human dermal papilla cells

H&E:

Hematoxylin and eosin

HF:

Hair follicles

HPLC:

High performance liquid chromatography

IGF-1:

Insulin-like growth factor-1

KGF:

Keratinocyte growth factor

MXD:

Minoxidil

OD:

Optical density

p-AKT:

Phospho protein kinase B

PBS:

Phosphate buffer saline

PDI:

Polydispersity index

PXRD:

Powder X-ray diffraction

P4:

Indole boron difluoride P4 fluorescent probe

SA:

Stearic acid

SA-MOF:

SA surface-modified CD-MOF

SC:

Stratum corneum

SEM:

Scanning electron microscope

SHH:

Sonic hedgehog

RIPA:

Radioimmunoprecipitation assay

TES:

Testosterone

TGF-β:

Transformation growth factor-β

TS:

Tape-stripping

VEGF:

Vascular endothelial growth factor

References

  1. Ong JS, Seviiri M, Dusingize JC, Wu Y, Han X, Shi J, Olsen CM, Neale RE, Thompson JF, Saw RPM, et al. Uncovering the complex relationship between balding, testosterone and skin cancers in men. Nat Commun. 2023;14:5962.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  2. Inui S, Itami S. Molecular basis of androgenetic alopecia: from androgen to paracrine mediators through dermal papilla. J Dermatol Sci. 2011;61:1–6.

    Article  CAS  PubMed  Google Scholar 

  3. Inui S, Itami S. Androgen actions on the human hair follicle: perspectives. Exp Dermatol. 2013;22:168–71.

    Article  CAS  PubMed  Google Scholar 

  4. Tang X, Cao C, Liang Y, Han L, Tu B, Yu M, Wan M. Adipose-Derived Stem Cell Exosomes Antagonize the Inhibitory Effect of Dihydrotestosterone on Hair Follicle Growth by Activating Wnt/β-Catenin Pathway. Stem Cells Int 2023, 2023:5548112.

  5. Sánchez P, Serrano-Falcón C, Torres JM, Serrano S, Ortega E. 5α-Reductase isozymes and aromatase mRNA levels in plucked hair from young women with female pattern hair loss. Arch Dermatol Res. 2018;310:77–83.

    Article  PubMed  Google Scholar 

  6. Giatti S, Di Domizio A, Diviccaro S, Falvo E, Caruso D, Contini A, Melcangi RC. Three-dimensional proteome-wide scale screening for the 5-Alpha reductase inhibitor finasteride: identification of a Novel off-target. J Med Chem. 2021;64:4553–66.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  7. Devjani S, Ezemma O, Kelley KJ, Stratton E, Senna M. Androgenetic Alopecia: Therapy Update. Drugs. 2023;83:701–15.

    Article  PubMed  PubMed Central  Google Scholar 

  8. Dou j, Zhang Z, Xu X, Zhang X. Exploring the effects of Chinese herbal ingredients on the signaling pathway of alopecia and the screening of effective Chinese herbal compounds. J Ethnopharmacol. 2022;294:115320.

    Article  PubMed  Google Scholar 

  9. Wei D, Zhilun Y, Zhengtao W, Bei Y, Yijing R, Xiaoping L. Application of cardamonin to preparing medicine used for preventing and curing baldness. vol. CN 108272781 A. China; 2018.

  10. Liu Z, He Z, Ai X, Guo T, Feng N. Cardamonin-loaded liposomal formulation for improving percutaneous penetration and follicular delivery for androgenetic alopecia. Drug Deliv Transl Res. 2024;14:2444–60.

  11. Santos JS, Barradas TN, Tavares GD. Advances in nanotechnology-based hair care products applied to hair shaft and hair scalp disorders. Int J Cosmet Sci. 2022;44:320–32.

    Article  CAS  PubMed  Google Scholar 

  12. Pereira-Silva M, Martins AM, Sousa-Oliveira I, Ribeiro HM, Veiga F, Marto J, Paiva-Santos AC. Nanomaterials in hair care and treatment. Acta Biomater. 2022;142:14–35.

    Article  CAS  PubMed  Google Scholar 

  13. Pereira MN, Nogueira LL, Cunha-Filho M, Gratieri T, Gelfuso GM. Methodologies to Evaluate the Hair Follicle-Targeted Drug Delivery Provided by Nanoparticles. Pharmaceutics. 2023;15.

  14. Forgan RS, Smaldone RA, Gassensmith JJ, Furukawa H, Cordes DB, Li Q, Wilmer CE, Botros YY, Snurr RQ, Slawin AMZ, Stoddart JF. Nanoporous Carbohydrate Metal–Organic frameworks. J Am Chem Soc. 2012;134:406–17.

    Article  CAS  PubMed  Google Scholar 

  15. Hartlieb KJ, Ferris DP, Holcroft JM, Kandela I, Stern CL, Nassar MS, Botros YY, Stoddart JF. Encapsulation of Ibuprofen in CD-MOF and related bioavailability studies. Mol Pharm. 2017;14:1831–9.

    Article  CAS  PubMed  Google Scholar 

  16. Roy I, Stoddart JF. Cyclodextrin Metal–Organic frameworks and their applications. Acc Chem Res. 2021;54:1440–53.

    Article  CAS  PubMed  Google Scholar 

  17. Smaldone RA, Forgan RS, Furukawa H, Gassensmith JJ, Slawin AMZ, Yaghi OM, Stoddart JF. Metal–Organic frameworks from Edible Natural products. Angew Chem Int Ed. 2010;49:8630–4.

    Article  CAS  Google Scholar 

  18. Yang N, Wei L, Teng Y, Yu P, Xiang C, Liu J. Cyclodextrin-based metal-organic frameworks transforming drug delivery. Eur J Med Chem. 2024;274:116546.

    Article  CAS  PubMed  Google Scholar 

  19. Abánades Lázaro I, Chen X, Ding M, Eskandari A, Fairen-Jimenez D, Giménez-Marqués M, Gref R, Lin W, Luo T, Forgan RS. Metal–organic frameworks for biological applications. Nat Reviews Methods Primers. 2024;4:42.

    Article  Google Scholar 

  20. Hamedi A, Anceschi A, Patrucco A, Hasanzadeh M. A γ-cyclodextrin-based metal–organic framework (γ-CD-MOF): a review of recent advances for drug delivery application. J Drug Target. 2022;30:381–93.

    Article  CAS  PubMed  Google Scholar 

  21. Si Y, Luo H, Zhang P, Zhang C, Li J, Jiang P, Yuan W, Cha R. CD-MOFs: from preparation to drug delivery and therapeutic application. Carbohydr Polym. 2024;323:121424.

    Article  CAS  PubMed  Google Scholar 

  22. He Z, Zhang Y, Liu Z, Guo T, Ai X, He Y, Hou X, Feng N. Synergistic treatment of androgenetic alopecia with follicular co-delivery of minoxidil and cedrol in metal–organic frameworks stabilized by covalently cross-linked cyclodextrins. Int J Pharm. 2024;654:123948.

    Article  CAS  PubMed  Google Scholar 

  23. Wu T, Hou X, Li J, Ruan H, Pei L, Guo T, Wang Z, Ci T, Ruan S, He Y, et al. Microneedle-mediated Biomimetic Cyclodextrin Metal Organic frameworks for active targeting and treatment of hypertrophic scars. ACS Nano. 2021;15:20087–104.

    Article  CAS  PubMed  Google Scholar 

  24. Singh V, Guo T, Xu H, Wu L, Gu J, Wu C, Gref R, Zhang J. Moisture resistant and biofriendly CD-MOF nanoparticles obtained via cholesterol shielding. Chem Commun (Camb). 2017;53:9246–9.

    Article  CAS  PubMed  Google Scholar 

  25. Yang T-S, Liu T-T, Lin IH. Functionalities of chitosan conjugated with stearic acid and gallic acid and application of the modified chitosan in stabilizing labile aroma compounds in an oil-in-water emulsion. Food Chem. 2017;228:541–9.

    Article  CAS  PubMed  Google Scholar 

  26. Wang P, Fei P, Zhou C, Hong P. Stearic acid esterified pectin: Preparation, characterization, and application in edible hydrophobic pectin/chitosan composite films. Int J Biol Macromol. 2021;186:528–34.

    Article  CAS  PubMed  Google Scholar 

  27. Noor NM, Sheikh K, Somavarapu S, Taylor KMG. Preparation and characterization of dutasteride-loaded nanostructured lipid carriers coated with stearic acid-chitosan oligomer for topical delivery. Eur J Pharm Biopharm. 2017;117:372–84.

    Article  CAS  PubMed  Google Scholar 

  28. Abd E, Benson HAE, Roberts MS, Grice JE. Minoxidil Skin Delivery from Nanoemulsion Formulations Containing Eucalyptol or Oleic Acid: Enhanced Diffusivity and Follicular Targeting. Pharmaceutics. 2018;10.

  29. Grice JE, Ciotti S, Weiner N, Lockwood P, Cross SE, Roberts MS. Relative uptake of minoxidil into appendages and stratum corneum and permeation through human skin in vitro. J Pharm Sci. 2010;99:712–8.

    Article  CAS  PubMed  Google Scholar 

  30. He Y, Hou X, Guo J, He Z, Guo T, Liu Y, Zhang Y, Zhang J, Feng N. Activation of a gamma–cyclodextrin–based metal–organic framework using supercritical carbon dioxide for high–efficient delivery of honokiol. Carbohydr Polym. 2020;235:115935.

    Article  CAS  PubMed  Google Scholar 

  31. Li C, Chen C, Wei Y, Tan M, Zhai S, Zhao J, Wang L, Dai T. Cyclodextrin metal-organic framework as vaccine adjuvants enhances immune responses. Drug Deliv. 2021;28:2594–602.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  32. Ruan H, Long M, Li J, Zhang D, Feng N, Zhang Y. Sustained-release hydrogen-powered bilateral Microneedles integrating CD-MOFs for in situ treating allergic Rhinitis. Adv Healthc Mater. 2024;13:2400637.

    Article  CAS  Google Scholar 

  33. Birjega R, Matei A, Marascu V, Vlad A, Ionita MD, Dinescu M, Zăvoianu R, Corobea MC. Stearic Acid/Layered double Hydroxides Composite Thin films deposited by combined laser techniques. Molecules. 2020;25.

  34. Liu S, Wang H, Yang J. Influence of Preparation methods and nanomaterials on Hydrophobicity and Anti-icing Performance of Nanoparticle/Epoxy Coatings. Polym (Basel). 2024;16.

  35. Memon AH, Ismail Z, Aisha AF, Al-Suede FS, Hamil MS, Hashim S, Saeed MA, Laghari M, Abdul Majid AM. Isolation, characterization, Crystal structure elucidation, and Anticancer Study of Dimethyl Cardamonin, isolated from Syzygium Campanulatum Korth. Evid Based Complement Alternat Med. 2014;2014:470179.

    Article  PubMed  PubMed Central  Google Scholar 

  36. Kaden D, Dähne L, Knorr F, Richter H, Lademann J, Meinke MC, Patzelt A, Darvin ME, Jung S. Determination of the pH Gradient in Hair Follicles of Human Volunteers Using pH-Sensitive Melamine Formaldehyde-Pyranine Nile Blue Microparticles. Sensors. 2020;20.

  37. Dimde M, Sahle FF, Wycisk V, Steinhilber D, Camacho LC, Licha K, Lademann J, Haag R. Synthesis and validation of functional nanogels as pH-Sensors in the hair follicle. Macromol Biosci. 2017;17:1600505.

    Article  Google Scholar 

  38. He Y, Zhang W, Guo T, Zhang G, Qin W, Zhang L, Wang C, Zhu W, Yang M, Hu X, et al. Drug nanoclusters formed in confined nano-cages of CD-MOF: dramatic enhancement of solubility and bioavailability of azilsartan. Acta Pharm Sinica B. 2019;9:97–106.

    Article  Google Scholar 

  39. Xu J, Wu L, Guo T, Zhang G, Wang C, Li H, Li X, Singh V, Chen W, Gref R, Zhang J. A ship-in-a-Bottle strategy to create folic acid nanoclusters inside the nanocages of γ-cyclodextrin metal-organic frameworks. Int J Pharm. 2019;556:89–96.

    Article  CAS  PubMed  Google Scholar 

  40. Zhang W, Guo T, Wang C, He Y, Zhang X, Li G, Chen Y, Li J, Lin Y, Xu X, et al. MOF capacitates Cyclodextrin to Mega-load Mode for high-efficient delivery of Valsartan. Pharm Res. 2019;36:117.

    Article  CAS  PubMed  Google Scholar 

  41. Zhao R-n, Zhu B-w, Xu Y, Yu S-f, Wang W-j. Liu D-h, Hu J-n: Cyclodextrin-based metal-organic framework materials: classifications, synthesis strategies and applications in variegated delivery systems. Carbohydr Polym. 2023;319:121198.

    Article  CAS  PubMed  Google Scholar 

  42. Yu KF, Zhang WQ, Luo LM, Song P, Li D, Du R, Ren W, Huang D, Lu WL, Zhang X, Zhang Q. The antitumor activity of a doxorubicin loaded, iRGD-modified sterically-stabilized liposome on B16-F10 melanoma cells: in vitro and in vivo evaluation. Int J Nanomed. 2013;8:2473–85.

    Google Scholar 

  43. Zhang G, Huang L, Wu J, Liu Y, Zhang Z, Guan Q. Doxorubicin-loaded folate-mediated pH-responsive micelle based on Bletilla striata polysaccharide: release mechanism, cellular uptake mechanism, distribution, pharmacokinetics, and antitumor effects. Int J Biol Macromol. 2020;164:566–77.

    Article  CAS  PubMed  Google Scholar 

  44. AbouAitah K, Abdelaziz AM, Higazy IM, Swiderska-Sroda A, Hassan AME, Shaker OG, Szałaj U, Stobinski L, Malolepszy A, Lojkowski W. Functionalized Carbon nanotubes for Delivery of Ferulic Acid and Diosgenin Anticancer Natural agents. ACS Appl Bio Mater. 2024;7:791–811.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  45. Huang J, Deng G, Wang S, Zhao T, Chen Q, Yang Y, Yang Y, Zhang J, Nan Y, Liu Z, et al. A NIR-II Photoactivatable ROS Bomb with High-Density Cu(2) O-Supported MoS(2) Nanoflowers for Anticancer Therapy. Adv Sci (Weinh). 2023;10:e2302208.

    Article  PubMed  Google Scholar 

  46. Quan G, Pan X, Wang Z, Wu Q, Li G, Dian L, Chen B, Wu C. Lactosaminated mesoporous silica nanoparticles for asialoglycoprotein receptor targeted anticancer drug delivery. J Nanobiotechnol. 2015;13:7.

    Article  Google Scholar 

  47. Tsuchiya K, Horikoshi K, Fujita M, Hirano M, Miyamoto M, Yokoo H, Demizu Y. Development of hydrophobic cell-penetrating stapled peptides as drug carriers. Int J Mol Sci. 2023;24.

  48. Wu J, Peng H, Lu X, Lai M, Zhang H, Le XC. Binding-mediated formation of Ribonucleoprotein Corona for efficient delivery and control of CRISPR/Cas9. Angew Chem Int Ed Engl. 2021;60:11104–9.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  49. Yao C, Tai Z, Wang X, Liu J, Zhu Q, Wu X, Zhang L, Zhang W, Tian J, Gao Y, Gao S. Reduction-responsive cross-linked stearyl peptide for effective delivery of plasmid DNA. Int J Nanomed. 2015;10:3403–16.

    CAS  Google Scholar 

  50. Su R, Fan W, Yu Q, Dong X, Qi J, Zhu Q, Zhao W, Wu W, Chen Z, Li Y, Lu Y. Size-dependent penetration of nanoemulsions into epidermis and hair follicles: implications for transdermal delivery and immunization. Oncotarget. 2017;8:38214–26.

    Article  PubMed  PubMed Central  Google Scholar 

  51. Qi J, Hu X, Dong X, Lu Y, Lu H, Zhao W, Wu W. Towards more accurate bioimaging of drug nanocarriers: turning aggregation-caused quenching into a useful tool. Adv Drug Deliv Rev. 2019;143:206–25.

    Article  CAS  PubMed  Google Scholar 

  52. Radtke M, Patzelt A, Knorr F, Lademann J, Netz RR. Ratchet effect for nanoparticle transport in hair follicles. Eur J Pharm Biopharm. 2017;116:125–30.

    Article  CAS  PubMed  Google Scholar 

  53. Patzelt A, Lademann J. Recent advances in follicular drug delivery of nanoparticles. Expert Opin Drug Deliv. 2020;17:49–60.

    Article  CAS  PubMed  Google Scholar 

  54. Kim MJ, Seong K-Y, Kim DS, Jeong JS, Kim SY, Lee S, Yang SY, An B-S. Minoxidil-loaded hyaluronic acid dissolving microneedles to alleviate hair loss in an alopecia animal model. Acta Biomater. 2022;143:189–202.

    Article  CAS  PubMed  Google Scholar 

  55. Gentile P, Garcovich S. Advances in Regenerative Stem Cell Therapy in Androgenic Alopecia and Hair Loss: Wnt Pathway, Growth-Factor, and Mesenchymal Stem Cell Signaling Impact Analysis on Cell Growth and Hair Follicle Development. Cells. 2019;8.

  56. Muangsanguan A, Linsaenkart P, Chaitep T, Sangta J, Sommano SR, Sringarm K, Arjin C, Rachtanapun P, Jantanasakulwong K, Phimolsiripol Y et al. Hair Growth Promotion and Anti-Hair Loss Effects of By-Products Arabica Coffee Pulp Extracts Using Supercritical Fluid Extraction. Foods. 2023;12.

  57. Tan JJY, Pan J, Sun L, Zhang J, Wu C, Kang L. Bioactives in Chinese Proprietary Medicine modulates 5α-Reductase activity and gene expression Associated with Androgenetic Alopecia. Front Pharmacol. 2017;8:194.

    Article  PubMed  PubMed Central  Google Scholar 

  58. Harshuk-Shabso S, Dressler H, Niehrs C, Aamar E, Enshell-Seijffers D. Fgf and wnt signaling interaction in the mesenchymal niche regulates the murine hair cycle clock. Nat Commun. 2020;11:5114.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  59. Song M, Shim J, Song K. Oral administration of Lactilactobacillus Curvatus LB-P9 promotes hair regeneration in mice. Food Sci Anim Resour. 2024;44:204–15.

    Article  PubMed  PubMed Central  Google Scholar 

  60. Li W, Man X-Y, Li C-M, Chen J-Q, Zhou J, Cai S-Q, Lu Z-F, Zheng M. VEGF induces proliferation of human hair follicle dermal papilla cells through VEGFR-2-mediated activation of ERK. Exp Cell Res. 2012;318:1633–40.

    Article  CAS  PubMed  Google Scholar 

  61. Truong VL, Bak MJ, Lee C, Jun M, Jeong WS. Hair Regenerative Mechanisms of Red Ginseng Oil and Its Major Components in the Testosterone-Induced Delay of Anagen Entry in C57BL/6 Mice. Molecules. 2017;22.

  62. Morinaga H, Mohri Y, Grachtchouk M, Asakawa K, Matsumura H, Oshima M, Takayama N, Kato T, Nishimori Y, Sorimachi Y, et al. Obesity accelerates hair thinning by stem cell-centric converging mechanisms. Nature. 2021;595:266–71.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  63. Haslam IS, Zhou G, Xie G, Teng X, Ao X, Yan Z, Smart E, Rutkowski D, Wierzbicka J, Zhou Y, et al. Inhibition of shh signaling through MAPK activation controls Chemotherapy-Induced Alopecia. J Invest Dermatology. 2021;141:334–44.

    Article  CAS  Google Scholar 

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Funding

This work was sponsored by National Natural Science Foundation of China [82304732], the Postdoctoral Fellowship Program of CPSF under Grant Number [GZC20232456], the Fellowship from the China Postdoctoral Science Foundation under Grant Number [2024M752966], Innovative Research Team of High-level Local University in Shanghai [SZY20220315].

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Author notes

  1. Zehui He and Zhenda Liu contributed equally to this work.

Authors and Affiliations

  1. School of Pharmacy, Shanghai University of Traditional Chinese Medicine, No.1200, Cai-lun Road, Pudong District, Shanghai, 201203, P.R. China

    Zhenda Liu, Yongtai Zhang, Teng Guo & Nianping Feng

  2. School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, 450001, Henan Province, China

    Zehui He

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Contributions

All authors contributed to the conception and design of this manuscript. The original draft of the manuscript, investigation, and formal analysis were performed by He and Liu. Zhang reviewed, and edited the study. The investigation and methodology by Guo. Feng supervised the study. All authors read and approved the final manuscript.

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Correspondence to Nianping Feng.

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The animal experiments were conducted with the approval of the Laboratory Animal Ethical and Welfare Committee of Shanghai University of Traditional Chinese Medicine.

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He, Z., Liu, Z., Zhang, Y. et al. Modulating metal-organic frameworks by surface engineering of stearic acid modification for follicular drug delivery and enhanced hair growth promotion. J Nanobiotechnol 23, 118 (2025). https://doiorg.publicaciones.saludcastillayleon.es/10.1186/s12951-025-03234-z

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Journal of Nanobiotechnology

ISSN: 1477-3155

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