442760 From Nanofiltration to Layer-By-Layer Assembly Membranes with Porins

Monday, November 9, 2015
Exhibit Hall 1 (Salt Palace Convention Center)
Cassandra Porter1, Sebastian Hernandez1, Xinyi Zhang2, Yinan Wei2 and Dibakar Bhattacharyya1, (1)Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY, (2)Department of Chemistry, University of Kentucky, Lexington, KY

Membranes provide selective barriers that allow certain molecules to pass through them based on charge and size restriction and provide an avenue for chemical separation that requires less energy than more common thermal separation processes. To introduce viewers to the key variables governing membrane selectivity, this poster will first address the differences in the rejection of various divalent salts by a nanofiltration membrane.   

            Even more impressive than artificial membranes are the biological membranes that nature offers, with higher selectivity, resistance to fouling, and regenerative capabilities. Thus, incorporating into membranes the structures responsible for high biological performance could potentially increase stimulus-responsive behavior and salt rejection while attaining larger fluxes than other highly selective membranes. In order to achieve proper alignment and stabilization of biomolecules, certain techniques are utilized. The second focus of this research is to explain the process and behavior of the layer-by-layer assembly of polycations and polyanions. Multilayers of electrolytes have been shown to increase the number of immobilized biomolecules by 25-fold with insignificant distortion of biomolecules.

            Porins, or cylindrical beta barrel protein pores, are the biomolecule of interest in this research. Membranes with solely porins acting as their channels could produce novel behaviors and transport only small metabolites while rejecting macromolecules. These beta barrel proteins are immobilized within the pores of polyvinylidene fluoride (PVDF) membranes using layers of poly(acrylic acid) (PAA) hydrogel intercalated through in situ free radical polymerization and poly(allylamine) hydrochloride (PAH) accumulated during convective flow. The major challenge with this study is achieving an orientation of the porins parallel to the length of membrane pores so fluids may flow through their channels. The number of electrolytic layers, methods of functionalizing the membranes and immobilizing the porins, and the effect of the polyion chosen for the final layer are examined to achieve proper porin alignment and stability. 

Acknowledgement: This research is made possible by NSF KY EPSCOR and by NIH-NIEHS-SRC.

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