Polyethylene Oxide Chain Density and Uremic Toxin Effects on Plasma Protein Adsorption

Abstract

Protein adsorption to implanted biomaterials can direct host responses and lead to health complications and device failure. Polyethylene oxide (PEO) is the gold standard film for reducing non-specific protein adsorption. Although polymer chain density is an important factor in determining PEO’s protein-resistant behavior, limited studies have related PEO chain density changes to the adsorption of plasma proteins. Besides, existing literature on protein adsorption primarily offers insights from the use of blood from healthy donors, neglecting changes in the blood that occur in unhealthy patients. In chronic kidney disease (CKD), uremic toxins (UTXs) accumulate in the blood compartment and significantly alter the blood composition. For the advancement of low-fouling surfaces for blood-contacting biomaterials and in the quest for personalized dialysis, addressing this knowledge gap is necessary. To examine this, PEO films with variable chain densities and two different end groups, methoxy (-OCH3) and hydroxy (-OH), were prepared and characterized using dynamic contact angle, ellipsometry, and X-ray photoelectron spectroscopy (XPS), to confirm the successful deposition of PEO. Protein adsorption experiments were conducted using human plasma with and without UTXsto investigate their effect on protein adsorption. It was observed that fibrinogen, albumin, factor XI, complement C3, and IgG were the major proteins detected on both methoxy and hydroxy-PEO-modified films. The addition of UTXs substantially increased protein adsorption to methoxy-terminated PEO films, whereas no specific trend was observed for hydroxy-PEO films. The effect of chain densities did not exhibit a consistent pattern but significantly affected the adsorption of many proteins. This knowledge is integral to developing the standard protein adsorption profile and subsequent advancement of surface technologies that enable personalized treatment strategies for patients with kidney failure.