{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,12]],"date-time":"2026-10-12T21:18:43Z","timestamp":1791839923855,"version":"4.3.4"},"reference-count":24,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2023,5,6]],"date-time":"2023-05-06T00:00:00Z","timestamp":1683331200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Major Science and Technology Innovation Project in Shandong Province","award":["2019JZZY011001"],"award-info":[{"award-number":["2019JZZY011001"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Polymers"],"abstract":"<jats:p>Although keratin can effectively repair hair fibres and enhance their moisture content and flexibility, it has a relatively low affinity for hair. In this study, the effects of transglutaminase (TGase)\u2014commonly used to catalyse crosslinking of proteins or amino acids\u2014in crosslinking serine and hydrolysed wool keratin to repair damaged hair and protect healthy hair were studied. Treatment with a repair solution containing hydrolysed wool keratin, serine, and TGase improved the physical and chemical properties of damaged hair samples. The alkali solubility of damaged hair samples decreased by 50.53%, fracture stress increased from 1.031 to 1.806 N, and fracture strain increased from 9.51 to 19.88 mm. Fourier transform infrared spectroscopy and X-ray analysis showed that amide bonds increased in damaged hair samples treated with the repair solution and hair crystallinity increased. Differential scanning calorimetry showed that the repair solution improved the thermal stability of damaged hair. After five cycles of washing, the effects of the repair solution were still apparent in damaged hair samples. The enzymatic solution had stronger repair effects than general hair care products and reduced water loss rates in damaged hair samples; repaired hair samples were also softer and brighter. The repair solution was effective in protecting healthy hair samples against chemical damage. The materials used to prepare the repair solution are all bio-based, and treatment with this product is safer and longer lasting.<\/jats:p>","DOI":"10.3390\/polym15092210","type":"journal-article","created":{"date-parts":[[2023,5,8]],"date-time":"2023-05-08T02:03:31Z","timestamp":1683511411000},"page":"2210","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":9,"title":["Enzymatic Crosslinking of Amino Acids Improves the Repair Effect of Keratin on Hair Fibre"],"prefix":"10.3390","volume":"15","author":[{"given":"Yang","family":"Liu","sequence":"first","affiliation":[{"name":"State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan 250353, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jingjing","family":"Liu","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan 250353, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jing","family":"Xiao","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan 250353, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,5,6]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"438","DOI":"10.1016\/j.jsb.2006.04.008","article-title":"Structural analysis of human hair single fibres by scanning microbeam SAXS","volume":"3","author":"Kajiura","year":"2006","journal-title":"J. Struct. Biol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"153","DOI":"10.1590\/S1984-82502009000100019","article-title":"Hair fiber characteristics and methods to evaluate hair physical and mechanical properties","volume":"45","author":"Velasco","year":"2009","journal-title":"Braz. J. Pharm. Sci."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"S106","DOI":"10.1067\/mjd.2003.276","article-title":"Human hair: A unique physicochemical composite","volume":"6","author":"Wolfram","year":"2003","journal-title":"J. Am. Acad. Dermatol."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"58594","DOI":"10.1039\/C6RA08797C","article-title":"Effects of chemical structures of polycarboxylic acids on molecular and performance manipulation of hair keratin","volume":"6","author":"Song","year":"2016","journal-title":"RSC Adv."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"591","DOI":"10.1016\/j.tibtech.2021.09.010","article-title":"Biotechnology of functional proteins and peptides for hair cosmetic formulations","volume":"40","author":"Tinoco","year":"2022","journal-title":"Trends Biotechnol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"805","DOI":"10.1016\/j.ijbiomac.2017.03.052","article-title":"Peptide\u2014Protein interactions within human hair keratins","volume":"101","author":"Cruz","year":"2017","journal-title":"Int. J. Biol. Macromol."},{"key":"ref_7","first-page":"34","article-title":"Factors affecting the ther-mal contraction of keratin fibres","volume":"229","author":"Watt","year":"1969","journal-title":"J. Polym. Sci. Pol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"43","DOI":"10.1007\/s10973-010-0691-2","article-title":"Effect of wool keratin proteins and peptides on hair water sorption kinetics","volume":"102","author":"Barba","year":"2010","journal-title":"J. Therm. Anal. Calorim."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Villa, A.L.V., Arag\u00e3o, M.R.S., Dos Santos, E.P., Mazotto, A.M., Zingali, R.B., De Souza, E.P., and Vermelho, A.B. (2013). Feather keratin hydrolysates obtained from microbial keratinases: Effect on hair fiber. BMC Biotechnol., 13.","DOI":"10.1186\/1472-6750-13-15"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"315","DOI":"10.1016\/j.foodchem.2014.09.019","article-title":"Action of microbial transglutaminase (MTGase) in the modification of food proteins: A review","volume":"171","author":"Gaspar","year":"2015","journal-title":"Food Chem."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"793","DOI":"10.1080\/15440478.2018.1534187","article-title":"Effect of Transglutaminase Enzyme on Physico-mechanical Properties of Rambouillet Wool Fiber","volume":"17","author":"Soun","year":"2020","journal-title":"J. Nat. Fibers"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"277","DOI":"10.1177\/0040517507078788","article-title":"Enzyme-mediated Crosslinking of Wool. Part II: Keratin and Transglutaminase","volume":"77","author":"Cardamone","year":"2007","journal-title":"Text. Res. J."},{"key":"ref_13","unstructured":"Lin, Z. (2016). Study on mTG Enzyme-Catalyzed Reinforcement of Fragile Wool Fabrics. [Ph.D. Thesis, Zhejiang Sci-Tech University]."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"195","DOI":"10.2306\/scienceasia1513-1874.2021.016","article-title":"Repair of damaged hair protein fiber by jointly using transglutaminase and keratin","volume":"47","author":"Li","year":"2021","journal-title":"Scienceasia"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"193","DOI":"10.1042\/bj1100193","article-title":"Evidence of homology in a high-sulphur protein fraction (SCMK-B2) of wool and hair alpha-keratins","volume":"110","author":"Gillespie","year":"1968","journal-title":"Biochem. J."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"786","DOI":"10.1177\/004051755902901003","article-title":"An Empirical Method for Estimating the Degree of Crystallinity of Native Cellulose Using the X-ray Diffractometer","volume":"29","author":"Segal","year":"1959","journal-title":"Text. Res. J."},{"key":"ref_17","unstructured":"The Textile Journal Group (2006). Total Colour Management in Textiles, Woodhead."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"307","DOI":"10.1016\/S0022-2860(99)00173-8","article-title":"Application of fourier-transform infrared and raman spectroscopy to study degradation of the wool fiber keratin","volume":"511","author":"Wojciechowska","year":"1999","journal-title":"J. Mol. Struct."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"369","DOI":"10.1016\/j.carbpol.2018.09.074","article-title":"Disulfide bond reconstruction: A novel approach for grafting of thiolated chitosan onto wool","volume":"203","author":"Zhang","year":"2018","journal-title":"Carbohydr. Polym."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"26","DOI":"10.1111\/ics.12663","article-title":"Penetration of different molecular weight hydrolyzed keratins into hair fibers and their effects on the physical properties of textured hair","volume":"43","author":"Malinauskyte","year":"2021","journal-title":"Int. J. Cosmet. Sci."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"10","DOI":"10.3109\/10242422.2012.644436","article-title":"Protein disulphide isomerase-mediated grafting of cysteine-containing peptides onto over-bleached hair","volume":"30","author":"Fernandes","year":"2012","journal-title":"Biocatal. Biotransform."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"458","DOI":"10.1111\/ics.12065","article-title":"Potential of human \u03b3D-crystallin for hair damage repair: Insights into the mechanical properties and biocompatibility","volume":"35","author":"Ribeiro","year":"2013","journal-title":"Int. J. Cosmet. Sci."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1055","DOI":"10.1007\/s12221-010-1055-z","article-title":"Restoring Important Hair Properties with Wool Keratin Proteins and Peptides","volume":"11","author":"Barba","year":"2010","journal-title":"Fibers Polym."},{"key":"ref_24","first-page":"120","article-title":"Preparation of rabbit hair keratin and its application in sunscreen cosmetics","volume":"30","author":"Yi","year":"2018","journal-title":"Res. Dev. Nat. Prod."}],"container-title":["Polymers"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2073-4360\/15\/9\/2210\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T19:30:43Z","timestamp":1760124643000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2073-4360\/15\/9\/2210"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,5,6]]},"references-count":24,"journal-issue":{"issue":"9","published-online":{"date-parts":[[2023,5]]}},"alternative-id":["polym15092210"],"URL":"https:\/\/doi.org\/10.3390\/polym15092210","relation":{},"ISSN":["2073-4360"],"issn-type":[{"value":"2073-4360","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,5,6]]}}}