Enzyme-modified casein fibers and their potential application in drug delivery

Enzymatic crosslinking of casein fibers was done using Transglutaminase (TGase) to improve the mechanical properties, particularly the stability in aqueous conditions and make them suitable for controlled drug release application. Crosslinking casein with 5 U/g of TGase in the spinning dope for 60 min at 25 °C increased the tenacity and tensile strain of the fibers from 0.40 g/den and 4.2 % to 0.70 g/den and 23.1 %, respectively. The stability of the fibers in water at different pH levels was considerably improved after the enzymatic crosslinking. The SDS-PAGE electrophoresis confirmed that higher molecular weight proteins were formed in TGase-crosslinked fibers. Thermogravimetric analysis (TGA) showed that TGase treated fibers also had a higher thermal degradation temperature than the non-crosslinked fibers. Crosslinked fibers exhibited delayed and lower rate of drug release from the fibers suggesting their suitability for controlled drug release.