Impact of monoolein on aquaporin1-based supported lipid bilayer membranes

Abstract

Aquaporin (AQP) based biomimetic membranes have attracted considerable attention for their potential water purification applications. In this paper, AQP1 incorporated biomimetic membranes were prepared and characterized. The morphology and structure of the biomimetic membranes were characterized by in situ atomic force microscopy (AFM), infrared absorption spectroscopy, fluorescence microscopy, and contact angle measurements. The nanofiltration performance of the AQP1 incorporated membranes was investigated at 4 bar by using 2 g l−1 NaCl as feed solution. Lipid mobility plays an important role in the performance of the AQP1 incorporated supported lipid bilayer (SLB) membranes. We demonstrated that the lipid mobility is successfully tuned by the addition of monoolein (MO). Through in situ AFM and fluorescence recovery after photo-bleaching (FRAP) measurements, the membrane morphology and the molecular mobility were studied. The lipid mobility increased in the sequence DPPC < DPPC/MO (RMO = 5/5) < DOPC/MO (RMO = 5/5) < DOPC, which is consistent with the flux increment and salt rejection. This study may provide some useful insights for improving the water purification performance of biomimetic membranes.

Performance evaluation of interfacial polymerisation-fabricated aquaporin-based biomimetic membranes in forward osmosis

“…Meanwhile, further increases in P/L, packing defects, and pore defects in the biomimetic membrane led to lower water uxes and separation effective. 40,41 Hence, a P/L value of 1 : 200 is close to the optimal ratio for ABM-1 and ABM-2.…”

Biomimetic membranes: A critical review of recent progress

“…The technological improvements of RO processes are continuous, with much research aimed at minimizing due largely to high pressure requirements, membrane fouling and scaling issues [11,197]. Aquaporin-based membranes are more permeable than commercial RO membranes by two orders of magnitude [174]. Thus, the implementation of biomimetic membranes in the RO process could help to attain good water flux using low pressure and thus save hundreds of millions of dollars by reducing annual electrical energy expenses.…”

“…Monoolein, a relatively simple lipid molecule, has also been suggested to be a viable polymorph for the fabrication of biomimetic membranes because of its ability to maintain its stability and self-assemble into various crystalline structures under different temperature and solvent compositions [173]. The incorporation of monoolein into proteoliposomes in SLBs might improve mobility and reduce inactivity of proteins [174]. Wang et al [174] reported that lipid mobility in AQP1-embedded SLB can be successfully tuned through the addition of monoolein.…”

“…The incorporation of monoolein into proteoliposomes in SLBs might improve mobility and reduce inactivity of proteins [174]. Wang et al [174] reported that lipid mobility in AQP1-embedded SLB can be successfully tuned through the addition of monoolein. The nanofiltration performance of AQP1-embedded membranes was studied by using 2,000 ppm NaCl as the feed solution in a nanofiltration setup at an applied pressure of 4 bar.…”

“…The nanofiltration performance of AQP1-embedded membranes was studied by using 2,000 ppm NaCl as the feed solution in a nanofiltration setup at an applied pressure of 4 bar. Monoolein is a non-toxic and biocompatible monoglyceride which, when added to a lipid bilayer, can improve molecular mobility in a bilayer because it can provide additional free volume through its cisdouble bond [174,175]. Meanwhile, to evaluate the real impact of monoolein integration with lipid bilayers on membrane water permeability and salt rejection, further investigations at higher applied pressures are required.…”