Poly(L-lactic acid) Depth Filter Membrane Prepared by Nonsolvent-Induced Phase Separation with the Aid of a Nonionic Surfactant

Abstract

Poly(L-lactic acid) (PLLA) membranes prepared via a nonsolvent-induced phase separation method with a nonionic surfactant (Tween 80) have been applied as depth lters in the ltration of bacterial cell suspensions and mammalian cell broths. Finger-like pores captured the cells inside the membrane, avoiding the formation of a dense cell cake on the membrane surface. The ltration rate of lactic acid bacterial cell suspensions increased 4-5 times during depth ltration compared to that observed during screen ltration with a smooth surface. During depth ltration, the connected cellular structure as well as the nger-like pores captured the bacterial cells. The plots of the reciprocal of permeation ux vs. the permeate volume per unit ltration area suggest that capturing the bacterial cells in the pores resulted in reduced blocking constants during depth ltration compared to screen ltration. During the ltration of CHO cell broths, the cells were captured in the nger-like pores of the PLLA depth lter and on the screen lter membranes of cellulose acetate. The permeation ux was sustained at high levels for longer durations during depth ltration compared to screen ltration, although the initial ux was lower than that in screen ltration. The PLLA depth lter will be useful as a pre lter in the ltration of suspensions of compressible bacterial and mammalian cells.

Protein adsorption characteristics of nanoparticle-assembled hollow microspheres of hydroxyapatite and their composites with PLLA microporous membranes

“…In the integration carried out in this study, a PLLA porous membrane with open finger-like pores was used as the membrane. The membrane structure becomes suitable for the facile composition of the microspheres and porous membrane by filtering a suspension of the microspheres [28, 59]. Fig.…”