Thermodynamics and Molecule Landscape of Protein Corona.

The protein corona redefines interfacial identity and dictates subsequent biological responses of nanoparticles. Nevertheless, the thermodynamic principles governing its formation and spatiotemporal evolution at the single-particle level remain poorly resolved. To address this, we developed an integrated surface plasmonic imaging and optical tweezing platform for real-time, label-free tracking of protein corona assembly on individual Au nanoparticles (AuNPs). By precise modulation of local temperature and pH, we demonstrated that corona formation can be energetically driven by minimization of interfacial free energy and coupled with protein molecule rearrangements. Kinetic analyses revealed distinct adsorption mechanisms: bovine serum albumin (BSA) followed Lagergren pseudo-first-order kinetics, whereas tetrameric hemoglobin (Hb) exhibited pseudo-second-order behavior, reflecting differences in molecular packing and structural stability. Furthermore, single-molecule fluctuation dissection of IgG/anti-IgG interactions revealed that the protein corona significantly quenched thermal fluctuations and restricted configurational transitions.