Kinetics of charge-dependent reversible condensation of reflectin nanostructures†

Reflectins are unique cephalopod proteins found in specialized cells. They form fast triggerable nanostructures in vivo that play a crucial role in light reflection and camouflage. We investigated the rapid kinetics of in vitro reversible self-assembly of two recombinant reflectin sequences (R1b and R6) using pH variations as a trigger. By employing experimental and theoretical approaches across scales, we demonstrated that R6 exhibits superior reversibility and faster assembly kinetics. R6 maintained reversible assembly for up to 7 rapid pH cycles, with changes occurring in less than 20 minutes. This enhanced performance is attributed to R6's higher content of pH-sensitive residues and favorable charge distribution. Our findings impact the design of reflectin-inspired artificial biophotonic systems, offering potential applications in sensors, adaptive optics, and dynamic display technologies.