Mean-Field Model of Immobilized Enzymes Embedded in a Grafted Polymer Layer

Abstract

Two-dimensional mean-field lattice theory is used to model immobilization and stabilization of an enzyme on a hydrophobic surface using grafted polymers. Although the enzyme affords biofunctionality, the grafted polymers stabilize the enzyme and impart biocompatibility. The protein is modeled as a compact hydrophobic-polar polymer, designed to have a specific bulk conformation reproducing the catalytic cleft of natural enzymes. Three scenarios are modeled that have medical or industrial importance: 1), It is shown that short hydrophilic grafted polymers, such as polyethylene glycol, which are often used to provide biocompatibility, can also serve to protect a surface-immobilized enzyme from adsorption and denaturation on a hydrophobic surface. 2), Screening of the enzyme from the surface and nonspecific interactions with biomaterial in bulk solution requires a grafted layer composed of short hydrophilic polymers and long triblock copolymers. 3), Hydrophilic polymers grafted on a hydrophobic surface in contact with an organic solvent form a dense hydrophilic nanoenvironment near the surface that effectively shields and stabilizes the enzyme against both surface and solvent.

Active Packaging Coatings

“…Drug delivery with controlled release has sparked new interest in various fiber morphologies, as well as micro and nanoparticles and hydrogels. Embedding and blending is often paired with cross-linking techniques to improve retention of the support material's physical properties [109]. Biopatterning, in which specific patterns of immobilized biomolecules are defined with micron or submicron resolution, also has potential application in active packaging coatings.…”

Characteristics and impact of Taq enzyme adsorption on surfaces in microfluidic devices

“…While, to the best of our knowledge, no detailed adsorption study is available for the Taq, a number of prior studies using other commonly used proteins such as lysozyme (Assis 2003;Beverung et al 1999;Haynes et al 1994;Luk et al 2000;Norde and Favier 1992;Prime and Whitesides 1993;Story et al 1991;Yoon and Garrell 2003), creatine phosphokinase (Pancera and Petri 2002), glucose 6-phosphate dehydrogenase (Pancera and Petri 2002), bovine serum albumin Norde and Favier 1992;Popat and Desai 2004;Sweryda-Krawiec et al 2004;Yoon and Garrell 2003), immunoglobulin (Vermeer et al 2001), and many other proteins/enzymes have invariably shown unique adsorption rates on different materials, including some of the materials/surface presented in this work. The differences in rate of adsorptions may be attributed to a number of inter-playing mechanisms commonly postulated in literature including: tendency of protein hydrophobic/hydrophilic chain to either align towards (or away) from the adsorbing surface (Koutsopoulos et al 2004;Orasanu-Gourlay and Bradley 2006;Pancera and Petri 2002), surface free-energy (i.e., charge) (Noinville et al 2002), electrostatic attraction/repulsion (Assis 2003;Haynes et al 1994;Yoon and Garrell 2003), thermodynamics Norde and Haynes 1995), unique interfacial tension between the protein and adsorbing surface (Beverung et al 1999), and relationship between protein penetration and steric hindrance from the structure of the protein and adsorbing material (Luk et al 2000;Moskovitz and Srebnik 2005;Sofia et al 1998). It is worth noting that many authors have suggested that the adsorption mechanisms themselves may not be fully understood Luk et al 2000;Sweryda-Krawiec et al 2004;…”

Novel immobilization process of a thermophilic catalase: efficient purification by heat treatment and subsequent immobilization at high temperature

“…Because enzymes are fragile proteins, great effort has been taken to prevent their denaturation and inactivation during immobilization [16,23,24]. To avoid structural damage to the enzymes, the conditions for enzyme immobilization are always very mild (e.g., pH 7.0 and 20°C) [24][25][26].…”