Modification of Silica Xerogels with Polydopamine for Lipase B from Candida antarctica Immobilization

Abstract

Silica xerogels have been proposed as a potential support to immobilize enzymes. Improving xerogels’ interactions with such enzymes and their mechanical strengths is critical to their practical applications. Herein, based on the mussel-inspired chemistry, we demonstrated a simple and highly effective strategy for stabilizing enzymes embedded inside silica xerogels by a polydopamine (PDA) coating through in-situ polymerization. The modified silica xerogels were characterized by scanning and transmission electron microscopy, Fourier tranform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and pore structure analyses. When the PDA-modified silica xerogels were used to immobilize enzymes of Candida antarctica lipase B (CALB), they exhibited a high loading ability of 45.6 mg/gsupport, which was higher than that of immobilized CALB in silica xerogels (28.5 mg/gsupport). The immobilized CALB of the PDA-modified silica xerogels retained 71.4% of their initial activities after 90 days of storage, whereas the free CALB retained only 30.2%. Moreover, compared with the immobilization of enzymes in silica xerogels, the mechanical properties, thermal stability and reusability of enzymes immobilized in PDA-modified silica xerogels were also improved significantly. These advantages indicate that the new hybrid material can be used as a low-cost and effective immobilized-enzyme support.

Novel Silica Hybrid Xerogels Prepared by Co-Condensation of TEOS and ClPhTEOS: A Chemical and Morphological Study

“…Silica hybrid gels are among the so-called organic modified silica (ORMOSILs). Nowadays, these materials are being used for multiple applications such as the adsorption of metals in water [ 1 , 2 , 3 ], catalyst support [ 4 , 5 , 6 ], support for luminescent compounds [ 7 , 8 , 9 ], anti-corrosive or fungicide coatings [ 10 , 11 , 12 , 13 ], and biomedicine [ 14 , 15 , 16 , 17 , 18 , 19 ]. The key behind the tunability of the properties of these materials is the synergetic effect that generates the coexistence, at a nanometric scale, of an inorganic skeleton with flexible and functional organic constituents [ 20 , 21 ].…”