(784f) Layer-by-Layer Assemblies for Membrane-Based Enzymatic Catalysis

Abstract:
Biomolecule immobilization within the porous domain
of microfiltration membrane media is a classic, well- studied approach for
applications in such areas as enzymatic catalysis and separations. While
considerable progress has been made in regards to understanding the optimal
conditions for the preservation of the activity of these immobilized
biomolecules, much more work is required in order to fully quantify these
precise conditions for each type of biomolecule. An effective approach to biomolecule immobilization is layer-by-layer (LbL) functionalization,
which holds promise due to the electrostatic nature of these assemblies. Since,
in nature, enzymes and proteins exist in an electrostatic environment, the
layer-by-layer approach offers a relatively high magnitude of immobilized biomolecular activity, as opposed to other methods of
immobilization such as covalent attachment.

The goal of this study is to define and quantify the
optimal electrostatic environments for enzymatic immobilization in order to maximize
enzyme activity and overall membrane reaction effectiveness. Glucose oxidase (GOx) was used as a model
enzyme within a poly(acrylic acid) (PAA)-poly(allylamine hydrochloride) (PAH)-functionalized poly(vinylidene fluoride) (PVDF) microfiltration membrane pores.
The local activities of enzymes need to be quantified as a function of the
properties of positively and negatively charged functional species within the
porous domain, surface charge, enzyme immobilization configuration, and bulk membrane
properties. The study is mainly focused on the analyses of these data,
particularly the comparison of functionalized surface chemistry with local
enzymatic configuration and activity. The understanding of the effect of these
surfaces and enzyme locations will be important for advancing the LbL methods.  Enzyme
activities are quantified using batch experiments under convective modes
through pressure modulations.