Effect of sterilization techniques on the physicochemical properties of polysulfone hollow fibers

Abstract

Sterilized hollow-fiber membranes are used in hemodialysis, ultrafiltration, bioprocessing, and tissue engineering applications that require a stable and biocompatible surface. In this study, we demonstrated significant changes in the fiber physicochemical properties with different methods of sterilization. Commercial polysulfone (PS) hollow fibers containing poly(vinyl pyrrolidone) were subjected to standard ethylene oxide (ETO), sodium hypochlorite (bleach), and electron-beam (e-beam) sterilization techniques followed by analysis of the surface hydrophilicity, morphology, and water-retention ability. E-beam sterilization rendered more hydrophilic fibers with water contact angles near 47 compared to the ETO-and bleachtreated fibers, which were each near 56. Atomic force microscopy revealed lumen root mean square (rms) roughness values near 19 nm for all three sterilization methods;however, e-beam-sterilized and bleach-treated fibers had significantly higher ($ 106 nm) rms values for the outer wall compared to the ETO-sterilized fibers ($ 39 nm). The increased hydrophilicity and surface area of the e-beamsterilized fiber were reflected by a greater water evaporation rate than that of the ETO-treated fiber. These results demonstrate that common sterilization methods may significantly and distinctly alter the polymer membrane physicochemical properties, which may, in turn, impact the performance and, in particular, surface fouling. For tissue engineering and bioprocessing applications, these changes may be leveraged to promote cell adhesion and spreading.

Hemodialysis effect on platelet count and function and hemodialysis-associated thrombocytopenia

“…Electron beam sterilization alters the surface property of PS-PVP membranes, increasing their hydrophilicity. 79 Different sterilization properties of membranes can affect their biocompatibility. 32 Against such an interpretation is the results of a study that to date has been reported only in abstract form by Ryder et al; 80 predialysis platelet counts in 2043 prevalent dialysis patients were compared before and after changing from a non-electronbeam-sterilized PS dialyzer to one sterilized by electron beam irradiation.…”

Hemodialysis membrane surface chemistry as a barrier to lipopolysaccharide transfer

“…Increasing or reducing PVP concentration is reflected in the lower and higher contact angles for the high‐ and low‐PVP membranes, respectively, compared to the Optiflux standard. Bleaching of PS‐PVP membranes has been shown to cause an increase in hydrophobicity and net negative charge, attributed to chain scission of PVP via radical reactions . This appears to be occurring here as bleaching Optiflux fibers for 2 min increased fiber hydrophobicity.…”

“…This highlights how solute transport characteristics are greatly dependent on both the membrane properties and the reprocessing (sterilization) technique . Extended bleach sterilization renders PS/PVP fibers increasingly hydrophobic, which may favor LPS binding.…”

“…The altered PVP concentrations investigated here are maintained within this range. Bleach‐treated Optiflux fibers were prepared through exposure to 0.57% effective sodium hypochlorite content from the dialysate side at 70°C for 2 min in order to limit possible membrane damage during sterilization . Importantly, pore size change as measured by sieving coefficient was negligible among the modified membranes (data not shown).…”

“…For all membranes tested, sessile drop contact angle analysis was performed on both the outer surface and lumen of the fibers using the method previously described . To access the lumen, the fiber was cut longitudinally and spread open on to double‐sided tape.…”