Facile and Efficient Enzymatic Methods for Harvesting or Removal of Cuticle Cells from Human Hair Shafts

ABSTRACT

Human hair fibers are structurally organized as a cortex protected by an outer scaly sheath (cuticle). Developing methods to isolate these two compartments will help to elucidate their roles in hair biology and develop potential applications. Herein, we developed enzymatic methods for human hair cuticle cell harvesting or removal. After a single treatment with esperase for three days, cuticle cells were released from hair shafts and effectively harvested by a series of filtration, centrifugation, and resuspension steps. Separately, combining L-cysteine and either esperase or savinase could remove the entire cuticle layer to obtain descaled hair fibers. The physical and chemical structures, and performance of the isolated cuticle cells and descaled hair samples were characterized using electron microscopy, FTIR, solid state ¹³C NMR, TGA, and DSC. Results show that the harvested cuticle cells contain mainly β-sheets and random coil structures, while descaled hair samples contain more α-helical structures. Harvested cuticle cells have greater thermal stability than the descaled hair samples below 260°C. The enzymatic methods developed in this study are convenient and easily controlled. They are effective not just for cuticle cell harvesting but also for surface modification and structure disintegration of hair fibers.

摘要

人发纤维的主体结构为皮质层, 由外层鳞片状鞘 (角质层) 保护. 开发分离鳞片和皮质的方法将有助于阐明它们在头发生物学中的作用和开发其潜在的应用. 在此, 我们开发了一套通过酶来分离和去除人头发表面鳞片细胞的方法. 用Espase单独处理头发三天后,鳞片细胞从发干中释放出来, 并通过一系列过滤, 离心和再悬浮步骤可有效收集. 另外, 结合L-半胱氨酸和esperase或savinase可以去除整个鳞片层, 获得脱鳞片头发. 使用电子显微镜, FTIR, 固态13C NMR, TGA和DSC对分离的鳞片细胞和去鳞片头发样品的物理和化学结构以及性能进行了表征. 结果表明, 分离的鳞片细胞角蛋白主要含有β-折叠和无规卷曲结构, 而去鳞片头发角蛋白α-螺旋结构含量高.在260°C以下，分离鳞片细胞的热稳定高于去鳞片头发样品。 本研究开发的酶法简便, 易于控制， 它们不仅可有效分离和去除头发鳞片,还可用于毛发纤维的表面修饰和结构分解.

KEYWORDS:

• Human hair
• cuticle
• esperase
• savinase
• enzymatic treatment
• keratin

关键词:

• 人发
• 角质层
• 酶处理
• 角蛋白

Highlight

1 Intact human hair cuticles were successfully released and harvested with a single treatment with esperase for 72 h, at high yields of about 3.4% of total hair mass.

2 L-cysteine can be combined with either esperase or savinase to remove cuticles from human hair within 4 h.

3 Cuticles collected were pure and consistent; compared to the descaled hair, cuticle is more thermally stable and contains higher content of β-sheet and random coil structure.

Acknowledgments

The authors would like to acknowledgement the NTU Center of High Field NMR Spectroscopy and Imaging and the Facility for Analysis, Characterization, Testing, and Simulation (FACTS), for their support in NMR and electron microscopy analysis.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This research was supported by the Agency for Science, Technology and Research (A*STAR) under its Acne and Sebaceous Gland Program & Wound Care Innovation for the Tropics IAF-PP (H17/01/a0/008 & H17/01/a0/0L9), the China Scholarship Council (Grant No. 201906790039 to N.Z.), and the National Natural Science Foundation of China (51673087).