Digestive enzyme coronas on quercetin-loaded starch nanoparticles: Effects on enzyme activity and bioactive compound release

Abstract

This study systematically investigated the formation and properties of digestive enzyme coronas on quercetin-loaded starch nanoparticles (QSNP). The nanoparticle size increases from 106.3 ± 3.1 nm (bare QSNP) to 220.6 ± 2.2 nm (α-amylase), 256.0 ± 8.6 nm (pepsin), 291.7 ± 5.7 nm (trypsin), and 218.5 ± 3.1 nm (lipase), indicating enzyme adsorption. FTIR and circular dichroism confirmed structural modifications of enzymes upon nanoparticle binding, including secondary structure alterations. Enzyme interactions were observed: α-amylase targeted amorphous starch regions, while trypsin and lipase formed stable coronas through bile salt mediation. Notably, corona formation differentially modulated enzymatic activity, with α-amylase showing 6-fold inhibition and lipase exhibiting 4-fold activation. Quercetin release was strongly influenced by corona composition, following distinct kinetic models: Fickian diffusion (α-amylase corona, n = 0.43), first-order kinetics (trypsin), and erosion-controlled release (lipase). These findings elucidate enzyme corona effects on starch digestion and nutraceutical release, aiding controlled-delivery system design.

Keywords: Controlled release; Delivery system; Protein corona; Quercetin; Starch nanoparticles.