Disassembly and in vitro cell compatibility of α-lactalbumin particulates under physiologically relevant conditions

Protein self-assemblies in the form of ordered supramolecular structures such as particulates hold great potential as new biomaterials. However, research in this field is rarely conducted under physiologically relevant conditions but such studies are crucially needed to unravel the potential use of particulates and other amyloid structures in health sciences. In this study, particulates of α-lactalbumin (ALA) were prepared at different stages of maturation by thermal incubation. Disassembly of particulates in isotonic buffer, neutral pH and at 37 °C was investigated by simultaneously measuring Thioflavin T fluorescence intensity and light scattering. Freshly formed particulates quickly disassembled and displayed complete release of soluble ALA within 1 h. Mature particulates displayed slower disassembly kinetics with incomplete release of ALA within 1 h. The biocompatibility of particulates at different maturation stages to epithelial lung and fibroblast cells was assessed in vitro. Good cell compatibility was observed in the presence of the particulates and their released species. Our findings display protein particulates as biodegradable and highly tunable particles, promoting them as good candidates for drug delivery purposes.