Construction of Porous Bilayer Cellulose Acetate/Silk Fibroin Membranes for Bloodstream Infection Treatment

Abstract

The removal of harmful substances from blood is always a technological challenge to treat bloodstream infection (BSI). To this end, we explore the use of a phase-inversion and bilayer membrane cast process to construct porous bilayer cellulose acetate (CA)/silk fibroin (SF) composite membranes consisting of a big porous membrane (Max/Average/Min pore size 3.37:1.57:0.63 μm) and a small porous membrane (Max/Average/Min pore size 0.48:0.26:0.11 μm) to capture bacteria and endotoxins. Experiments demonstrated that the concentrations of CA and SF and the weight ratio of CA and SF played important roles in preparing porous CA/SF membranes with desirable pore size and high mechanical strength. In vitro and blood contact experiments demonstrated that the as-prepared porous CA/SF membranes had good hemocompatibility and antifouling properties. In vitro and harmful substance-contained blood contact experiments demonstrated that the porous bilayer CA/SF composite membranes could effectively capture high (106 CFU/mL bacteria and 300 EU/mL endotoxins) and low (102 CFU/mL bacteria and 5 EU/mL endotoxins) concentrations of Escherichia coli, Staphylococcus aureus, and endotoxins, and the ability of the porous bilayer CA/SF composite membranes to capture bacteria and endotoxins could be attributed to the big size of the pores and the affinity of the bacteria/endotoxins to CA/SF. Our work shows that porous bilayer CA/SF membranes have the potential for the treatment of BSI.