Two surface gradients of polyethylene glycol for a reduction in protein adsorption

Abstract

Polyethylene glycol (PEG) coatings have been commonly used in reducing protein adsorption with the intent of improving a biomaterial's biocompatibility. To elucidate the role of PEG surface density in reducing protein adsorption, two types of grafted PEG surface density gradients were evaluated for the adsorption and desorption of albumin and fibrinogen, two blood proteins. PEG density gradients were characterized using contact angle measurements and X-ray photoelectron spectroscopy. Total internal reflection fluorescence was used to measure protein adsorption kinetics and adsorption profiles on the two types of PEG gradients. The PEG gradient generated by the flow method decreased adsorption of both proteins in proportion to the PEG surface density; however, their desorption by buffer solution from the grafted PEG layer was not complete. In contrast, desorption of two proteins from the grafted PEG layer generated by a UV oxidation method resulted in near-zero adsorbed amount. The difference between the two types of gradients might have originated from counter-diffusion of PEG and water molecules occurring during the flow method procedure.

DMSA-Functionalized Mesoporous Alumina with a High Capacity for Selective Isolation of Immunoglobulin G

“…The high-resolution S 2p spectrum of DMSA−MA (Figure 3b) exhibits two peaks: a strong peak at 163.61 eV, representative of a C−S bond, 40 and a weak peak at 168.61 eV. This could be possibly due to excessive oxidation of thiols during the reaction, 41 indicating the sulfur atoms are oxidized to the sulfonate moiety. The fraction of sulfur in the oxidized state was around 0.27.…”