search for




 

Development of Hair Keratin Protein to Accelerate Oral Mucosal Regeneration
J Dent Hyg Sci 2023;23:369-77
Published online December 31, 2023;  https://doi.org/10.17135/jdhs.2023.23.4.369
© 2023 Korean Society of Dental Hygiene Science.

So-Yeon Kim

Department of Dental Hygiene, College of Health & Medical Sciences, Cheongju University, Cheongju 28503, Korea
Correspondence to: So-Yeon Kim, https://orcid.org/0000-0002-6735-2794
Department of Dental Hygiene, College of Health & Medical Sciences, Cheongju University, 298, Daeseong-ro, Cheongwon-gu, Cheongju 28503, Korea
Tel: +82-43-229-7908, Fax: +82-43-229-8969, E-mail: ksy0615@cju.ac.kr
Received December 5, 2023; Revised December 18, 2023; Accepted December 19, 2023.
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
Background: In this study, we investigated the potential use of keratin for oral tissue regeneration. Keratin is well-known for its effectiveness in skin regeneration by promoting keratinization and enhancing the elasticity and activity of fibroblasts. Because of its structural stability, high storability, biocompatibility, and safety in humans, existing research has predominantly focused on its role in skin wound healing. Herein, we propose using keratin proteins as biocompatible materials for dental applications.
Methods: To assess the suitability of alpha-keratin protein as a substrate for cell culture, keratin was extracted from human hair via PEGylation. Viabilities of primary human gingival fibroblasts (HGFs) and human oral keratinocytes (HOKs) were assessed. Fluorescence immunostaining and migration assays were conducted using a fluorescence microscope and confocal laser scanning microscope. Wound healing and migration assays were performed using automated software to analyze the experimental readout and gap closure rate.
Results: We confirmed the extraction of alpha-keratin and formation of the PEG-g-keratin complex. Treatment of HGFs with keratin protein at a concentration of 5 mg/ml promoted proliferation and maintained cell viability in the test group compared to the control group. HOKs treated with 5 mg/ml keratin exhibited a slight decrease in cell proliferation and activity after 48 hours compared to the untreated group, followed by an increase after 72 hours. Wound healing and migration assays revealed rapid closure of the area covered by HOKs over time following keratin treatment. Additionally, HOKs exhibited changes in cell morphology and increased the expression of the mesenchymal marker vimentin.
Conclusion: Our study demonstrated the potential of hair keratin for soft tissue regeneration, with potential future applications in clinical settings for wound healing.
Keywords : Gingival fibroblast, Human hair keratins, Oral keratinocytes, Oral mucosa, Wound regeneration
Introduction

1.Background

Tooth decay and periodontal disease go beyond causing pain in the teeth or oral mucosa1). The periodontium is an intricate structure composed of specialized tissues supporting the teeth, and most periodontal surgeries involve invasive procedures, such as resection of the gingiva or alveolar bone2). Periodontal wound healing is a multifaceted process involving the regeneration of periodontal tissues3). Following wound formation, the body engages in a sophisticated physio-logical process known as wound healing, which is charac-terized by four sequential yet overlapping phases: hemostasis, inflammation, proliferation, and remodeling4). The perio-dontal wound healing process differs slightly from cutaneous wound healing, but shares similarities with fetal healing, resulting in minimal scarring. The primary goal of periodo-ntal wound healing is to achieve stable healing and enhance treatment outcomes5). Rapid oral wound healing can help reduce inflammation, which is a crucial aspect of healing. However, the relationship between oral wound healing and periodontal disease remains unclear. A specialized oral envi-ronment comprising saliva and microorganisms can influence defect formation and wound healing6,7). Therefore, the mechanisms that drive regeneration in the oral cavity remain to be fully investigated.

Keratin, the primary protein present in the outer epi-dermis, has garnered significant attention as a natural wound dressing material because of its outstanding bio-compatibility, lack of toxicity, and broad applicability8,9). This natural protein is commonly found in the hair, wool, horns, hooves, and nails. Keratin possesses diverse cell- inding motifs, such as leucine-aspartate-valine and arginine- glycine-aspartate, which facilitate cell attachment and proliferation9,10). Studies have demonstrated that keratin plays a pivotal role in all stages of wound healing, inclu-ding hemostasis, inflammation, proliferation, and remo-deling11,12). Therefore, keratin-based materials are considered ideal for wound dressings. However, the function of hair keratin in the oral tissue remains poorly understood.

In the present study, we isolated hair keratin proteins and explored their potential to regenerate soft tissues in the oral cavity. Initially, we enhanced the hydration rate and probed the biological stability of keratin by assessing physicochemical changes. Subsequently, we investigated its effects on wound healing in the oral mucosa to eluci-date its physiological role in the oral cavity. Based on our findings, we propose that keratin is a promising candidate for oral soft tissue regeneration.

2.Objectives

This study aimed to extract alpha-keratin and form a PEG-g-keratin complex. This study aimed to prepare kera-tin proteins derived from human hair to ensure that they are nontoxic and biocompatible for use in oral soft tissue regeneration. We also assessed the fundamental biological properties of these proteins in gingival fibroblasts and oral keratinocytes. Additionally, we investigated the impact of epithelial–mesenchymal transition (EMT) on the migra-tion of oral keratinocytes and its role in in vitro wound healing. This study focused on developing various dental applications based on keratin.

Materials and Methods

1.Extraction and PEGylation of human hair keratin proteins

Human hair samples were washed using a mild deter-gent and were subsequently rinsed multiple times with distilled water. To remove lipids, the samples were immersed in a solution of chloroform and methanol (1:1, v/v) for 24 hours, immersed in a solution of chloroform and methanol (2:1, v/v), and washed with distilled water (Junsei Chemical, Tokyo, Japan). Human hair samples were air-dried and subjected to additional aqueous washes until all residues were eliminated.

The dried hair samples were then soaked in a 2% acetic acid solution for 12 hours at 37°C and 300 rpm and washed several times to eliminate any remaining oxidants. For neutralization, a solution (400 ml) consisting of 5% 2- ercaptoethanol, 5 M urea, 2.6 M thiourea, and 25 mM Tris-HCl (pH 8.5) was used for every 20 g of hair samples, undergoing a 72-hour process at 50°C and 400 rpm. The supernatant was collected after centrifugation at 3,500 rpm for 20 minutes.

Keratin samples were dialyzed against distilled water using a 12 to 14 kDa cutoff dialysis membrane (Sigma Aldrich, St. Louis, MO, USA). The dialyzed samples were then lyophilized into powder form. Hair protein extracts were separated using a Bolt Bis-Tris (Thermo Scientific, Waltham, MA, USA) 4% to 12% mini gel under reducing conditions in Bolt MES SDS Running Buffer at 165 V. Protein quantification was conducted using the Bradford assay with bovine serum albumin as the standard and approximately 200 mg of protein was loaded into each well. NuPAGE antioxidants (Thermo Scientific) were added to prevent protein re-oxidation during electropho-resis. Blue Plus2 Pre-Stained Standard (Thermo Scientific) was used as the molecular weight marker. The gels were subsequently stained with 0.1% (w/v) Coomassie Brilliant Blue G-250 (Sigma Aldrich) overnight and destained in a solution containing 10% (v/v) acetic acid and 40% (v/v) methanol until clear bands were observable.

2.Culture of normal oral keratinocytes and human gingival fibroblasts

Normal human oral keratinocytes (HOKs) were culti-vated in T75 cell culture flasks at 37°C and 5% CO2 using an oral keratinocyte medium with oral keratinocyte growth supplement and 1% penicillin/streptomycin. The cells were maintained in the dark and the medium was refreshed every other day. Human gingival fibroblasts (HGFs) were cultured in a fibroblast medium containing 10% fetal bovine serum and penicillin/streptomycin (10 µg/ml). Me-dium was replaced every three days (Thermo Scientific). Upon reaching 70% to 80% confluence, cells were deta-ched from the flask using 0.05% trypsin and 0.1% ethyle-nediaminetetraacetic acid (EDTA) solution, washed twice, resuspended in media, and used for in vitro cell experi-ments. HOKs and HGFs were obtained from ScienCell Research Laboratories (Carlsbad, CA, USA).

3.Cytotoxicity test of PEG-g-keratin

HGFs and HOK cells were seeded at a density of 1×10 cells/well in 48-well plates and incubated in DMEM supplemented with 10% FBS and 1% penicillin/strepto-mycin for 24 hours to achieve stabilization. Subsequently, keratin (5 mg/ml) was added. After 24, 48, and 72 hours of incubation, the cultures were aspirated, washed with DPBS, and diluted 10-fold using the Cell Counting Kit-8 solution (CCK) kit (Thermo Fisher Scientific, Pittsburgh, PA, USA). The mixture was then incubated at 37°C for 1.5 hours using aluminum foil to block the light. After 30 minutes of incubation, 200 ml of the solution was transferred to a 96-well plate, and absorbance was measured at a wavelength of 450 nm using a 96-well format plate reader (BioTek Instruments Inc., Winooski, VT, USA).

4.In vitro migration assay

In vitro wound modeling was conducted using HOK cells treated with mitomycin C (Sigma Aldrich) at a con-centration of 10 mg/ml. HOK cells, treated with or without mitomycin C, were placed on two culture inserts (Ibidi, Munich, Germany) at a density of 7×10 cells/ml in each well, and the culture medium was added to achieve a final volume of 70 ml. After 24 hours, the culture insert was carefully removed using tweezers and replaced with normal medium (ScienCell Research Laboratories). The cells were added to each plate and inoculated with treated or untreated HOK cells. The remaining two plates were cultured in medium containing a 0.5% (w/v) PEG-g- keratin complex. The degree of movement was assessed after incubation at 37°C for 12 and 24 hours. The cell-free area was determined using the public domain program ImageJ 1.34s (National Institutes of Health, Bethesda, MD, USA). Additionally, Ibidi offers a FastTrack AI image analysis service (Ibidi Software 1.5.4). Three independent cell lines were used in this study.

5.Immunofluorescence staining

Cells were fixed and treated with a rabbit anti-vimentin antibody (1:100; Santa Cruz Biotechnology, Delaware, CA, USA) for 4 hours at room temperature. Subsequently, cells were treated with Alexa Fluor594 (1:500) fluorescein for 2 hours at room temperature. Fluorescent images were captured using a FluoView 300 fluorescence microscope (Olympus, Tokyo, Japan). Each sample was then submerged in 4% paraformaldehyde (Sigma Aldrich) at room temperature for 30 minutes. After washing three times with DPBS, 0.1% Triton-X-100 (Sigma Aldrich) was added, and the sample was incubated at room temperature for 45 minutes.

Next, the blocking buffer (Merck, St. Louis, MO, USA) was incubated with the samples at room temperature for 1 hour. Subsequently, the primary antibody vimentin (Cell Signaling Technology, Denver, MA, USA) was used at a 1:200 dilution in Antibody Diluent (Cell Signaling Tech-nology) and incubated overnight at 4°C. The secondary antibody Alexa Fluor 594 anti-mouse IgG (Merck) was used at a ratio of 1:1000 and diluted at room temperature. The cells were incubated for 1 to 2 hours. To stain the cell nucleus, 4',6-diamidino-2-phenylindole (DAPI; Sigma Aldrich) was used. The samples were observed under a fluorescence microscope (BX51; Olympus).

6.Statistical analysis

Quantitative and statistical values derived from in vitro analyses were compared. The data collected in this study were analyzed using IBM SPSS Statistics (version 22.0; IBM Corp., Armonk, NY, USA). The results are presented as the mean±standard deviation. An unpaired Student’s t-test was used to evaluate the differences between two groups. One-way analysis of variance (ANOVA) with post hoc analysis using Tukey’s test was used for comparisons between multiple groups. The mean±standard error of the mean was obtained from at least three independent experiments. Statistical significance was set at p<0.05.

Results

1.Extraction and PEGylation characterization of human hair keratin protein

The SDS-PAGE analysis of keratin protein extracted from hair revealed that the resulting product had an approximate molecular weight of 50 kDa (monomer). This confirmed the successful extraction of keratin and the formation of the PEG-g-keratin complex. The primary com-ponent of keratin was determined to be a-keratin, as illustrated in (Fig. 1). Similarly, the molecular weight of the PEG-g-keratin complex was approximately 50 kDa (mono-mer), indicating the absence of decomposition or modifi-cation of the keratin molecules. Consequently, the utilization of PEG-g-keratin did not alter the composition of a- keratin, which retained its status as the primary constituent of both keratin and the PEG-g-keratin complex.

Fig. 1. Characteristics of human hair keratin extraction. (A) Images of keratin extraction from human hair. (B) 250 mg of protein was loaded for a quantitative analysis. The gels were stained with Coomassie brilliant blue. The extracted alpha keratin (major keratin) was characterized by specific bands in the analysis as shown in the figure. The staining revealed the presence of basic keratin monomers (∼50 kDa), acidic keratin monomers (∼45 kDa), and heterodimers in both keratin and PEG-g keratin.

Coomassie blue staining of the keratin extracts revealed that human hair extracts comprised basic keratin monomers (∼50 kDa), acidic keratin monomers (∼45 kDa), and kera-tin heterodimers (Fig. 1B). The presence of two bands in the acidic keratin region suggested the existence of at least two acidic keratin subtypes, with multiple bands within the keratin dimer region indicating diverse heterodimer combi-nations. The identity of human hair keratin was verified by blotting against total human hair keratin.

2.Cytotoxic effects of PEG-g-keratin on human gingival fibroblasts and human oral keratinocytes

To investigate the impact of PEG-g-keratin on HGF and HOK cell activity and growth, HOK cell and HGFs were treated with keratin at a concentration of 0.5 mg/ml for 24, 48, and 72 hours. Cytotoxicity assessment using the CCK kit after 24 and 48 hours of treatment showed a slight increase in the viability of HGFs compared to controls (Fig. 2). Although the survival rate of the HOK cells was similar to that of the control group after 24 hours, cons-picuous morphological changes occurred after 48 hours of treatment (Fig. 3B). The CCK assay indicated a decline in cell viability after 48 hours and recovery after 72 hours in the keratin-treatment group (Fig. 3C). Consequently, we inferred that HOK cells exhibited increased sensitivity to keratin treatment. According to the CCK assay, the viability of HGFs and HOK cells was not affected by the PEG-g-keratin complex at a concentration of 5 mg/ml (Fig. 2, 3).

Fig. 2. Cytotoxic Effects on Human Gingival Fibroblasts. (A) Light micrographs of the control group (CTR) after treatment with normal culture media for 72 hours. (B) After 72 hours of treatment with 5 mg/ml keratin, the keratin-treated group (K) was observed by light micrographs. The scale bars in (A) and (B) correspond to 200 mm. (C) Percentage survival of human gingival fibroblasts after treatment for 24, 48, and 72 hours. A one-way ANOVA followed by a post hoc test Tukey’s test was used for comparisons between groups (**p<0.01).

Fig. 3. Characterization of cellular morphological changes and cytotoxic effects of keratin on human oral keratinocytes. (A) Light micrographs of the control group (CTR) after treatment with normal culture media for 72 hours. (B) Optical micrographs of the keratin-treated group (K) after treatment with 5 mg/mL keratin for 72 hours. (A) CTR exhibited epithelial shapes, while (B) K displayed fibroblast-like morphological changes. The scale bars in (A) and (B) correspond to 200 mm. (C) Percentage viability of human oral keratinocytes after treatment with 5 mg/ml concentrations of keratin for 24, 48, and 72 hours. A one-way ANOVA followed by a post hoc test Tukey’s test was used for comparisons between groups (**p<0.01).

3.Effect of keratin on wound healing using human oral keratinocytes cells

In this study, we investigated the ability of keratin to promote wound healing. Micrographs of the wound healing assays involving mitomycin and keratin were captured using a culture insert placed in 2-well 35-mm dishes. Mic-roscopic images depicting wound closure in control cells treated with normal culture media were captured 0 and 12 hours after removal of the culture insert (Fig. 4). Cells treated with normal culture medium for 12 hours exhibited less migration than the keratin-treated cells (Fig. 4). Following a 12 hours incubation of HOKs with keratin (5 mg/ml), a statistically significant difference in the wounded areas was observed compared with the controls (Fig. 4C). Collectively, these findings suggest that keratin has the potential to enhance monolayer wound healing using HOKs.

Fig. 4. Analysis of human oral keratinocytes migration in the in vitro wound healing assay. The effect of keratin treatment on wound healing in human oral keratinocytes cell monolayer culture was evaluated by comparing a control group (CTR), which was treated with a normal medium, to a keratin-treatment group (K). (A) and (B) show micrographs in human oral keratinocytes after incubation for 0 and 12 hours. The scale bars correspond to 200 mm. (C) Shows the quantification after 12 hours of the percentage of areas repopulating the wound space. Central wound areas were selected from micrographs, and wound closure was assessed using ImageJ software. CTR consisted of the normal media treatment group, which was associated with higher closure rates in the keratin-treated group. Groups with letters above the data bar showed statistically significant results compared to CTR (***p<0.001).

4.Epithelial–mesenchymal transition- related migration assay

Cultured human hair keratinocytes were used to observe both the morphological changes in cells and migration (Fig. 4). The upregulation of vimentin expression in keratin- treated HOK cells indicated EMT. Furthermore, immuno-fluorescence characterization of HOK cells revealed the expression of vimentin (red) and DAPI (blue), which confirmed the morphological changes in the cells (scale bar=200 mm) (Fig. 5).

Fig. 5. Characterization of expression levels of the genes related to the process of epithelial–mesenchymal transition in human oral keratinocytes. (A) Images after immunofluorescence staining was performed on cells that were incubated with normal media for 2 days. (B) Confocal pictures after immunofluorescence staining was performed on cells that were incubated with keratin-treated media for 2 days. (A, B) The presence of vimentin was detected using immunofluorescence, and nuclei were stained with 4',6-diamidino-2-phenylindole (DAPI), depicted in blue. The scale bars correspond to 200 mm. (C) Expression of Vimentin was detected and quantified by immunofluorescence after 2 days in culture. Cells induce more EMT-related gene expression in the keratin-treated group (K) than the control group (CTR). The data are representative of three independent experiments.
Discussion

1.Interpretation

Periodontal disease, an inflammatory condition affecting both the hard and soft tissues supporting the teeth, is the leading cause of tooth loss1,4). Inflammation significantly hinders the healing of oral wounds and its reduction can accelerate the healing process5). If left untreated, it can lead to physical dysfunction and severe mental distress13). Notably, oral health is intricately connected to overall health, with the treatment of oral diseases and restoration of normal function having the potential to reverse systemic dysfunction2). Previous studies have demonstrated that keratin enhances oral wound healing by reducing infla-mmation14,15). Another study showed that hair keratin biofilms could release antibiotics and inhibit the growth of various oral bacteria, including Porphyromonas gingivalis16). These findings were validated by physicochemical anal-yses and release tests8,17). Keratin, a protein found in epithelial tissues such as hair, skin, and nails, forms the basis of other body parts such as horns, feathers, toenails, and fingernails18,19). Divided into true keratin and pseu-dokeratin, it is an insoluble protein known for its dura-bility and serves as an industrial material and biopolymer with applications across various fields20,21). Efficient pro-cesses for extracting keratin from human hair have led to the development of keratin-based biomaterials that have been successfully used for tissue regeneration18,22).

2.Key results and comparison

In this study, we analyzed the molecular weight of the protein to confirm the synthesis of the extracted PEGylated keratin. The PAA Shindai extraction method determines keratin solubility and examines the structure of alpha- keratins19,23). These proteins, which measure approxi-mately 10 nm, constitute a fundamental part of the cyto-skeleton and belong to the intermediate filament family24). Our results indicated that keratin plays a vital role in regulating the growth and migration of primary oral cells. PEGylated keratin treatment has demonstrated no toxicity to periodontal fibroblasts or dental keratinocytes, making it a potential biomaterial for applications in tissue enginee-ring, 3D printing, and drug delivery via hydration rate modification20,25). Overall, our findings suggested that PEGylated keratin is a promising and versatile bioma-terial. Previous studies have used keratin concentrations of 0.5∼5 mg/ml for skin regeneration; therefore, we used a lower concentration to study the biocompatibility with oral cells from oral mucosal tissues, which have similar histological properties to skin18,26). Furthermore, this study suggests that wound healing-related EMT and kerati-nocyte migration may be mediated by human hair-derived keratin protein. Oral wound repair typically lasts 2∼10 days and involves epithelial cell migration and proliferation, resulting in morphological changes to the mesenchymal phenotype7,12). Keratin promoted oral keratinocyte migra-tion and increased cytoskeletal protein expression (Fig. 4, 5). Epithelial cell plasticity, which is the ability to change cell type and function, occurs through transdifferentiation (metaplasia) or EMT. Type 1 EMT involves the transition of primitive epithelial cells into motile mesenchymal cells during early embryonic development, whereas type 2 EMT involves the transformation of mature epithelial or endo-thelial cells into tissue-resident fibroblasts in response to persistent inflammation11,14). Previous studies have indi-cated that vimentin biomarkers can be used to identify type 2 EMT because vimentin is expressed in adult epithelial cells subjected to various forms of damage or insult10,24). This study confirmed that the treatment of oral keratinocytes with keratin significantly affects cell migra-tion, induces EMT, and leads to increased cell migration. In conclusion, human hair-derived keratin is an excellent source for potent biomaterials. This review critically sum-marizes the molecular characteristics, cellular interactions, extraction strategies, and recent advances in the biome-dical applications of human hair keratin and offers valuable insights into its potential to enhance tissue regeneration in regenerative medicine.

3.Suggestion

Upon treatment with keratin, oral keratinocytes exhibit enhanced cell migration and increased expression of EMT- related proteins, validating its efficacy for wound healing. In summary, our study demonstrates that keratin proteins can be modified to enhance their solubility for medical applications. Using HGFs and oral keratinocytes, which are pivotal cells in the wound-healing process, we confir-med cell interactions and ensured biological stability. Specifically, keratin treatment increased cell migration and the expression of EMT-related proteins in oral kerati-nocytes, confirming its wound-healing properties. Conse-quently, we assert that PEGylated human hair keratin- based biomaterials are promising candidates for oral soft tissue regeneration.

4.Limitations

This study had several limitations. Oral tissue cells were used to examine the effects of human hair keratin on HGFs and keratinocytes. However, in wound healing studies, fibroblasts are considered a crucial wound-healing cell type that requires layered spheroids or layered models27). Although this study aimed to confirm hair keratin stability and wound-healing effects, its biological properties make limited contributions to the interpretation and conclusions regarding oral soft tissue regeneration. Future studies should focus on exploring the interactions between hair keratin and oral cells to enhance our understanding of their biological effects and mechanisms of action.

Acknowledgments

None.

Conflict of Interest

No potential conflict of interest relevant to this article was reported.

Ethical Approval

This project does not require IRB review because it is an experimental paper using commercially available cells.

Funding

This research was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (No. 2022R1C1C1010472).

Data availability

Raw data is provided at the request of the corresponding author for reasonable reason.

References
  1. Eke PI, Thornton-Evans G, Dye B, Genco R: Advances in surveillance of periodontitis: the Centers for Disease Control and Prevention periodontal disease surveillance project. J Periodontol 83: 1337-1342, 2012.
    https://doi.org/10.1902/jop.2012.110676.
    Pubmed KoreaMed CrossRef
  2. Wolf TG, Cagetti MG, Fisher JM, Seeberger GK, Campus G: Non-communicable diseases and oral health: an overview. Front Oral Health 2: 725460, 2021.
    https://doi.org/10.3389/froh.2021.725460.
    Pubmed KoreaMed CrossRef
  3. Sabharwal A, Stellrecht E, Scannapieco FA: Associations between dental caries and systemic diseases: a scoping review. BMC Oral Health 21: 472, 2021.
    https://doi.org/10.1186/s12903-021-01803-w.
    Pubmed KoreaMed CrossRef
  4. Haque MM, Yerex K, Kelekis-Cholakis A, Duan K: Advances in novel therapeutic approaches for periodontal diseases. BMC Oral Health 22: 492, 2022.
    https://doi.org/10.1186/s12903-022-02530-6.
    Pubmed KoreaMed CrossRef
  5. Pereira D, Sequeira I: A scarless healing tale: comparing homeostasis and wound healing of oral mucosa with skin and oesophagus. Front Cell Dev Biol 9: 682143, 2021.
    https://doi.org/10.3389/fcell.2021.682143.
    Pubmed KoreaMed CrossRef
  6. Hegde A, Ananthan AS, Kashyap C, Ghosh S: Wound healing by keratinocytes: a cytoskeletal perspective. J Indian Inst Sci 101: 73-80, 2021.
    https://doi.org/10.1007/s41745-020-00219-9.
    CrossRef
  7. Waasdorp M, Krom BP, Bikker FJ, van Zuijlen PPM, Niessen FB, Gibbs S: The bigger picture: why oral mucosa heals better than skin. Biomolecules 11: 1165, 2021.
    https://doi.org/10.3390/biom11081165.
    Pubmed KoreaMed CrossRef
  8. Richter JR, de Guzman RC, Greengauz-Roberts OK, Van Dyke M: Structure-property relationships of meta-kerateine biomaterials derived from human hair. Acta Biomater 8: 274-281, 2012.
    https://doi.org/10.1016/j.actbio.2011.08.020.
    Pubmed CrossRef
  9. An SY, Kim HS, Kim SY, et al.: Keratin-mediated hair growth and its underlying biological mechanism. Commun Biol 5: 1270, 2022.
    Erratum in: Commun Biol 5: 1406, 2022. Erratum in: Commun Biol 5: 1407, 2022. https://doi.org/10.1038/s42003-022-04232-9.
    Pubmed KoreaMed CrossRef
  10. Wang S, Taraballi F, Tan LP, Ng KW: Human keratin hydrogels support fibroblast attachment and proliferation in vitro. Cell Tissue Res 347: 795-802, 2012.
    https://doi.org/10.1007/s00441-011-1295-2.
    Pubmed CrossRef
  11. Sawaya AP, Uchiyama A, Hope E, et al.: Keratin 75 is a component of the LINC complex and has an essential role in mediating the SOX2 rapid healing response during wound repair. J Invest Dermatol 143: 494-498, 2023.
    https://doi.org/10.1016/j.jid.2022.08.054.
    Pubmed CrossRef
  12. Cho YD, Kim KH, Lee YM, Ku Y, Seol YJ: Periodontal wound healing and tissue regeneration: a narrative review. Pharmaceuticals (Basel) 14: 456, 2021.
    https://doi.org/10.3390/ph14050456.
    Pubmed KoreaMed CrossRef
  13. Martínez-García M, Hernández-Lemus E: Periodontal inflammation and systemic diseases: an overview. Front Physiol 12: 709438, 2021.
    https://doi.org/10.3389/fphys.2021.709438.
    Pubmed KoreaMed CrossRef
  14. Zuniga K, Isaac A, Christy S, et al.: Characterization of a human platelet lysate-loaded keratin hydrogel for wound healing applications in vitro. Int J Mol Sci 23: 4100, 2022.
    https://doi.org/10.3390/ijms23084100.
    Pubmed KoreaMed CrossRef
  15. Kang HJ, Ko N, Oh SJ, An SY, Hwang YS, Kim SY: Injectable human hair keratin-fibrinogen hydrogels for engineering 3D microenvironments to accelerate oral tissue regeneration. Int J Mol Sci 22: 13269, 2021.
    https://doi.org/10.3390/ijms222413269.
    Pubmed KoreaMed CrossRef
  16. Srinivasan V, Palanisamy P: A state-of-the-art review on keratin biomaterial as eminent nanocarriers for drug delivery applications. Lett Drug Des Discov 20: 245-263, 2023.
    https://doi.org/10.2174/1570180819666220620094943.
    CrossRef
  17. Lee H, Noh K, Lee SC, et al.: Human hair keratin and its-based biomaterials for biomedical applications. Tissue Eng Regen Med 11: 255-265, 2014.
    https://doi.org/10.1007/s13770-014-0029-4.
    CrossRef
  18. Sharma S, Gupta A: Sustainable management of keratin waste biomass: applications and future perspectives. Braz Arch Biol Technol 59: e16150684, 2016.
    https://doi.org/10.1590/1678-4324-2016150684.
    CrossRef
  19. Chilakamarry CR, Mahmood S, Saffe SNBM, et al.: Extraction and application of keratin from natural resources: a review. 3 Biotech 11: 220, 2021.
    https://doi.org/10.1007/s13205-021-02734-7.
    Pubmed KoreaMed CrossRef
  20. Zhang H, Liu P: Bio-inspired keratin-based core-crosslinked micelles for pH and reduction dual-responsive triggered DOX delivery. Int J Biol Macromol 123: 1150-1156, 2019.
    https://doi.org/10.1016/j.ijbiomac.2018.11.178.
    Pubmed CrossRef
  21. Kim SY, Park BJ, Lee Y, et al.: Human hair keratin-based hydrogels as dynamic matrices for facilitating wound healing. J Ind Eng Chem 73: 142-151, 2019.
    https://doi.org/10.1016/j.jiec.2019.01.017.
    CrossRef
  22. Yan RR, Gong JS, Su C, et al.: Preparation and applications of keratin biomaterials from natural keratin wastes. Appl Microbiol Biotechnol 106: 2349-2366, 2022.
    https://doi.org/10.1007/s00253-022-11882-6.
    Pubmed CrossRef
  23. Diwan H, Sah MK: Exploring the potential of keratin-based biomaterials in orthopedic tissue engineering: a comprehen-sive review. Emerg Mater 6: 1441-1460, 2023.
    https://doi.org/10.1007/s42247-023-00545-5.
    CrossRef
  24. Wang M, Wu Y, Li X, Dai M, Li S: IGJ suppresses breast cancer growth and metastasis by inhibiting EMT via the NF‑kB signaling pathway. Int J Oncol 63: 105, 2023.
    https://doi.org/10.3892/ijo.2023.5553.
    Pubmed KoreaMed CrossRef
  25. Fu L, Zhou X, Jiao Q, Chen X: The functions of TRIM56 in antiviral innate immunity and tumorigenesis. Int J Mol Sci 24: 5046, 2023.
    https://doi.org/10.3390/ijms24055046.
    Pubmed KoreaMed CrossRef
  26. Xu S, Sang L, Zhang Y, Wang X, Li X: Biological evaluation of human hair keratin scaffolds for skin wound repair and rege-neration. Mater Sci Eng C Mater Biol Appl 33: 648-655, 2013.
    https://doi.org/10.1016/j.msec.2012.10.011.
    Pubmed CrossRef
  27. Cialdai F, Risaliti C, Monici M: Role of fibroblasts in wound healing and tissue remodeling on Earth and in space. Front Bioeng Biotechnol 10: 958381, 2022.
    https://doi.org/10.3389/fbioe.2022.958381.
    Pubmed KoreaMed CrossRef


March 2024, 24 (1)
Full Text(PDF) Free

Social Network Service

Cited By Articles
  • CrossRef (0)
  • Download (113)

Author ORCID Information

Funding Information