Surface Modification of Poly(lactic acid) Membranes Via Immobilizing Carboxylic Graphene Oxide for Hemodialysis

The ideal hemocompatibility of poly(lactic acid) (PLA) blood-inert devices is highly desirable. In this work, the hemocompatible DA-g-GOCOOH nanosheets were immobilized onto the PLA membrane suface via a facile and green method. Dopamine (DA) molecules were grafted onto carboxylic graphene oxide (GOCOOH) nanoplatelets to obtain mussel inspired adhesive nanoplatelets (DA-g-GOCOOH) by means of carbodiimide chemistry method. Subsequently, DA-g-GOCOOH were adhered onto the PLA membrane surface via the adhesive ability of DA-g-GOCOOH in tris(hydroxymethyl)aminomethane hydrochloride buffer (tris-buffer). Attenuated total reflectance Fourier transform infrared spectra (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were applied to analyze the surface chemistry and morphology evolution of the fabricated membranes, which confirmed that DA-g-GOCOOH was successfully coated on PLA membrane. The results of water contact angle and zeta potentials demonstrated that the hydrophilicity and negativity of the modified PLA membranes were significantly improved. It effectively alleviated the surface adhesion of platelets, prolonged the recalcification time by 100s and declined the hemolysis ratio to less than 0.3%. Moreover, the modified PLA membrane exhibited good dialysis performances. When the immersing concentration of DA-g-GOCOOH was 2.0 mg/mL, the retention of BSA reached up to 95.6% and the clearance of urea and lysozyme was 65% and 24.5%, respectively. The present work provides a convenient strategy to improve the hydrophilicity and hemocompatibility of PLA membranes for their biomedical and blood-contacting applications such as hemodialysis.