Modified surface by poly(ethylene glycol) with looped conformation and its superior anticoagulant property

Abstract

Poly(ethylene glycol) (PEG) is currently the gold standard for anticoagulant coatings. Up to now, most researchers focused on the impact of chain length and grafting density of PEG on protein adsorption, but few concerned about the effect of PEG conformation. Gold surfaces of quartz crystal microbalance with dissipation (QCM-D) with looped (SH-PEG-SH) and linear (SH-PEG) PEGs with different molecular weights ( M W=1000 and M W=5000) are prepared. Subsequently, fibrinogen adsorption and anticoagulant properties are measured as well. The compositions and phase structures of PEG modified surfaces are characterized by XPS and AFM. Compared with linear PEG surface, we find that looped PEG surface more efficiently prohibits fibrinogen adsorption, and then has superior antiplatelet and anti-erythrocytes adhesions properties. Fibrinogen adsorption results suggest that when the molecular weight of PEG is low ( M W=1000), the main reason for the fibrinogen resistance of looped PEG is the large surface coverage; when the molecular weight of PEG is high ( M W=5000), the fibrinogen resistance mechanism of looped PEG is a combination of the high viscoelasticity and the large surface coverage. This article provides valuable evidence and guidance for anticoagulant coating and application of high-performance biomaterials.