Multienzymatic immobilization of laccases on polymeric microspheres:A strategy to expand the maximum catalytic efficiency

Laccase enzymes of were covalently coimmobilized on poly(glycidyl methacrylate) microspheres. The objective of this work was to create a biocatalyst that works efficiently in a wide range of pH. The coimmobilization was performed using two different strategies to compare the most efficient. The results showed that by correctly selecting the enzymes and concentrations involved in the commobilization, it is possible to obtain a biocatalyst that works efficiently at a wide pH range (2.0-7.0). The maximum activity values reached per gram of support for the obtained biocatalyst were 41.90 U (pH 3.0), 40.89 U (pH 4.0), and 39.54 U (pH 6.0). Moreover, the thermal, storage, and mechanical stabilities were improved compared to the free and single-immobilized laccases. It was concluded that enzymatic coimmobilization is an excellent alternative to obtain a robust biocatalyst that works in a wide pH range, with potential environmental and industrial applications

Preparation of bow tie-type methacrylated poly(caprolactone-co-lactic acid) scaffolds: Effect of collagen modification on cell growth

A branched methacrylated poly(caprolactone-co-lactic acid) and methacrylated poly(tetramethylene ether glycol) (PTMG-IEM) resins were synthesized. 1H-NMR spectroscopy, attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) spectroscopy, and gel permeation chromatography confirmed the chemical structures of copolymers. The photoinitiated polymerization of formulation composed of various amounts of methacrylated poly(caprolactone-co-lactic acid), PTMG-IEM, poly(ethylene glycol) diacrylate, water, and photoinitiator were performed. The curing reactions were followed by photo-DSC (Differential scanning calorimetry). Gel fraction was calculated from the insoluble part and found as =93%. Swelling and contact angles were measured, and all increased with the increasing amount of PTMG-IEM in network formulations. In vitro degradation studies were performed at 37 degrees C in phosphate-buffered saline (pH 7.4). Collagen-modified polymers were also prepared and introduced as a bioactive moiety to modify the polymer to enhance cell affinity. To compare the cell adhesion affinity to the polymer with and without collagen, cell growth experiments were performed. The results showed that collagen improves the cell adhesion onto the polymer surface. With the increasing amount of collagen, cell viability increases 86% (ECV304, p?<?0.05) and 83% (3?T3, p?<?0.05). Copyright (C) 2011 John Wiley & Sons, Ltd

Preparation of collagen modified photopolymers: A new type of biodegradable gel for cell growth

In this study a new branched methacrylated poly(propylene glycol-co-lactic acid) (PPG-PLA-IEM) and methacrylated cellulose acetate butyrate resin (CAB-IEM) were synthesized. Hydrogels with various amounts of PPG-PLA-IEM and CAB-IEM (25, 50 and 75 wt% IEM modified) were prepared by photopolymerization. Collagen tethered PEG-monoacrylate (PEGMA-collagen) was prepared and introduced as a bioactive moiety to modify the hydrogel in order to enhance cell affinity. In vitro attachment and growth of 3T3 mouse fibroblasts and human umbilical vein endothelial cells (HUVEC) on the hydrogels with and without collagen were also investigated. It was observed that, the collagen improves the cell adhesion onto the hydrogel surface. With the increasing amount of collagen, cell viability increased by 28% for ECV304 (P < 0.05) and 30% for 3T3 (P < 0.05)