Surface zwitterionization of hemocompatible poly(lactic acid) membranes for hemodiafiltration

Poly(lactic acid) (PLA) hemodiafiltration membranes were grafted by zwitterionic polymer to improve the fouling resistance and hemocompatibility. The surface zwitterionization was accomplished by dopamine inspired bromoalkyl initiator anchoring and subsequent atom transfer radical polymerization (ATRP) of zwitterionic poly(sulfobetaine methacrylate) (PSBMA). 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 zwitterionic PSBMA was successfully grafted on PLA membrane. The results of water contact angle and zeta potentials demonstrated that the hydrophilicity and negativity of the modified PLA membranes were highly improved, which effectively alleviated the surface adsorption of bovine serum albumin (BSA) and palates. Moreover, the modified PLA membrane exhibited good dialysis performances. When the polymerization time of PSBMA was 1 h, the water flux was 184 L m−2 h−1, while BSA retention reached up to 90%, and the clearance of urea and creatinine was maintained at 66% and 60%, respectively. The present work provides a convenient strategy to improve the hydrophilicity, anti-fouling and hemocompatibility of PLA membranes for their biomedical and blood-contacting applications such as hemodialysis.