Feathered Innovation: Transforming Recycled Keratin into Bioactive Micro/Nanoparticles for Advanced Drug Delivery Systems

Abstract

At present, great importance is attached to the use of waste biomass for the sustainable provision and fractionation of natural resources. This is particularly true for the production of biopolymers to promote the development of novel material products based on sustainability. This increased focus is driven by socio-economic and environmental considerations. Feathers from chickens are regarded as a waste from the poultry meat production sector. These organic wastes can be used as natural keratin sources for applications in the formation of nanoparticles to develop a new generation of multifunctional biocomposites. Thus, in this research keratin was isolated from feathers by extraction in subcritical water (SubCW) at 180°C, 20 bar for 1 h. This recycled keratin was used to develop advanced keratin-based particles. To investigate the complexation ability of keratin, three polyelectrolytes with different functional groups were used for particle synthesis at specific pH values, namely alginate with carboxyl groups, chitosan with amino groups, and penta-ionic sodium tripolyphosphate (TPP) with phosphate groups. Dynamic Light Scattering (DLS) analysis showed that complex formation between keratin-alginate and keratin-chitosan resulted in microparticles, and colloidal particles were formed only in the case of keratin-TPP. The ATR-FTIR spectra of the particles indicate that electrostatic interactions were the driving force for the complex formation between keratin and oppositely charged polyelectrolytes. The antioxidant activity of keratin diminishes upon the incorporation of alginate, chitosan, and TPP. The keratin-TPP particles, identified as optimal, underwent additional assessment as a drug delivery system for the model drug amoxicillin. UV/VIS spectroscopy indicated the successful encapsulation of amoxicillin (encapsulation efficiency of 69.24%), with a gradual release reaching up to 96% over a 6-hour period. Antimicrobial examination showed that the increased inhibition against both E. coli and S. aureus in the drug delivery system compared to pure amoxicillin can be attributed to the successful and controlled release of the drug from the particles. Consequently, these particles exhibit promising potential as a delivery system, offering simultaneous antioxidant and potentially antimicrobial properties.