Immunological and wound healing properties of keratin and its conformational variants extracted from ethically...

Keratin is an insoluble filamentous sulphur-rich protein constituting the bulk of epidermal appendages, such as hair, chicken feathers, nails, and claws. Being ubiquitously present, keratin's efficacy has been extensively evaluated for different tissue engineering applications. However, to date, no systematic study has investigated and compared two conformationally different keratins sourced from human hair and chicken feathers. The present research emphasizes the comparative therapeutic efficacy of keratins derived from human hair and chicken feathers. Herein, keratins isolated from both sources revealed differences in their molecular weights, as assessed using SDS-PAGE analysis. Notably, human hair-derived keratin (HK) has a molecular weight of 40-60 kDa, while chicken feather-derived keratin (CK) has a molecular weight of ∼10 kDa. FTIR, CD and Raman spectroscopy were performed to assess their conformational features, evidencing the α-helix dominance in HK but β-sheet/turn dominance in CK. Immunological assessment of the macrophage cell line demonstrated the anti-inflammatory property of keratin from each source, where HK showed a significantly higher anti-inflammatory property than CK. Furthermore, in vivo assessment showed that HK-treated wounds exhibit enhanced re-epithelialization and balanced COLI/COLIII deposition, indicating minimal scar formation compared with CK-treated ones. These findings underscore the potential of HK in clinical applications, particularly in wound care and regenerative medicines.