Complex Protein Patterns in Drying Droplets

Abstract

AbstractWe demonstrate that deposition patterns formed during drying droplets of aqueous protein solutions are complex, characteristic, and highly reproducible. Substrate, buffer as well as protein type are important factors largely influencing the patterned structure. Specifically, multiple growth zones in what we refer to as “soccer ball pattern” are formed when a droplet of albumin solution in sodium bicarbonate buffer is dried. Each growth zone has periodically patterned, concentric ringed structures surrounding a core at the center. Different macroscopic patterns are also found for streptavidin, fibrinogen, IgG antibody as well as rhodamine B base and polystyrene beads when droplets of their aqueous solutions are dried on the substrates with different degrees of hydrophilicity/hydrophobicity. Furthermore, distinguishable deposition patterns are formed in drying droplets of aqueous protein solutions containing albumin and fibrinogen at different ratios, suggesting that even the relative abundance of multiple proteins influences the deposition patterns. Since the protein pattern is reproducible for a given protein and variable among different proteins, the protein patterns from drying droplets might be useful to potentially identify a given protein under specific conditions.