(65ad) Studying the Effect of Pegylation On Fibrinogen Adsorption with Single-Molecule Resolution

Poly(ethylene) glycol (PEG) is widely accepted as an effective biocompatible surface due to its ability to inhibit protein adsorption. Total internal fluorescence microscopy (TIRFM) was used to study fibrinogen adsorption and desorption on pegylated fused silica on a single-molecule level. The results of this study show that pegylation does not strongly inhibit fibrinogen adsorption; however, there is also fibrinogen desorption from PEG. Conversely, there is no fibrinogen desorption from unmodified fused silica. The increased ability for adsorbed fibrinogen to later desorb from PEG is a possible explanation for why pegylated surfaces are more resistant to protein accumulation than unmodified fused silica. Moreover, on PEG there is an inverse relationship between fibrinogen fluorescence intensity and desorption rate. It is possible that brighter fibrinogen correspond to fibrinogen aggregates, which suggests that these aggregates do not desorb from pegylated surfaces as easily as single fibrinogen molecules.