Invigorating the assembling hierarchy of bovine serum albumin with nonionic surfactants of varying oxyethylene units in aqueous milieu.

The myriad applications of protein-surfactant interactions have generated ongoing interest among researchers in understanding the organization of protein-surfactant mixed assemblies. The present study investigated the solution behavior of a protein-surfactant mixture involving a native protein, Bovine serum albumin (BSA), and a series of nonionic surfactants, polyoxyethylene cetyl ethers (BC-X) with varying oxyethylene units (15, 20, 30) in the phosphate-buffered medium. UV-visible and fluorescence data confirmed the interactions between BSA functional groups and BC-X oxyethylene unit via polar interactions. Critical micelle concentration (CMC) decreased with an increased oxyethylene chain, contrasting the literature. Micropolarity data indicated that BC-X associates step-wise to form micelles with or without BSA. The lifetime, rotation correlation time, and fluorescence anisotropy of probes coherently endorsed the proposition, increasing to a maximum at pre-micellar regions before slightly decreasing and flattening at higher concentrations. Determining the extent of the α-helix structure and size of the protein-surfactant system indicated BSA unfolding and BSA - BC-X mixed assembly formation. The observations were linked to BC-X micelle's evolution alongside protein segments intertwined through oxyethylene units. Unlike the necklace-bead model proposed earlier, these micelles dangled in a water milieu resembling a necklace-pendant model. Lower CMC and intermediate micropolarity data in the present study suggest potential for sustainable drug delivery.