Encapsulation of biomolecules in silica gels

Abstract

A wide variety of biomolecules, ranging over proteins, enzymes, antibodies and even whole cells, have been embedded within sol-gel glasses. They retain their bioactivity and remain accessible to external reagents by diffusion through the porous silica. Sol-gel glasses can be cast into desired shapes and are optically transparent, so it is possible to couple optics and bioactivity to make photonic devices and biosensors. The high specificity and sensitivity of enzymes and antibodies allows the detection of traces of chemicals. Entrapped living cells can be used for the production of metabolites, the realization of immunoassays and even for cell transplantation.

Sol-gel technology in enzymatic electrochemical biosensors for clinical analysis

“…The high hydrophilicity and porosity make it compatible with biological species. More than that, synthesis of sol-gel materials is simple, fast and flexible (Avnir et al, 1994;Jin & Breman, 2002;Livage et al, 2001). The result of hydrolysis and polycondensation reactions is a colloidal sol that contains siloxane bonds (Si-O-Si network) and that, in presence of the target biomolecules or biological species, undergoes further condensation reactions till the gelation point is reached, in a time lasting from seconds to days.…”

“…entrapment in silica gels by sol-gel route is now history (Avnir et al, 1994;Gill & Ballesteros, 2000;Livage et al, 2001;Retz et al, 2000). Application of sol-gel technique in biosensing has been a logical consequence (Kunzelmann & Bottcher., 1997;de Marcos et al, 1999;Wang, 1999).…”

Cerâmicas bioativas: estado da arte

“…Entretanto, foi somente a partir de 1990 que tais pesquisas foram reiniciadas, quando Avnir e colaboradores 38 obtiveram resultados semelhantes aos de Dickey ao estudarem uma série de enzimas, incluindo a aspartase e a fosfatase alcalina aprisionadas em vidros derivados do TEOS. Atualmente, um grande número de trabalhos descreve o aprisionamento de diferentes espécies biológicas tais como enzimas, anticorpos, proteínas reguladoras, proteínas de ligação a membranas, ácidos nucléicos e, até mesmo, células inteiras em materiais compósitos produzidos pelo método sol-gel [39][40][41][42][43][44][45] . A imobilização de proteínas em vidros derivados desse méto-do apresenta grandes vantagens, tais como a de produzir materiais opticamente transparentes, ideais para desenvolvimento de sensores químicos e bioquímicos baseados em alterações de absorbância ou fluorescência.…”

Sol-Gel Thin Films Immobilized with Bromocresol Purple pH-Sensitive Indicator in Presence of Surfactants

“…Preparation of sol-gel matrices doped with some chemically and biologically active molecules is a promise route to chemical solid-state sensors [1][2][3][4]. The sol-gel technique is one of the most promising tools in material science.…”

“…The term sol-gel refers to a chemical process where metallic or semimetallic alkoxide precursors or their derivatives form composites at moderate temperatures through a chemical reaction that involves hydrolysis followed by polycondensation [2]. Hydrolysis and polycondensation of tetraethoxysilane in presence of water, organic solvent, and an acid/base catalyst result in the formation of the -Si-O-Si-threedimensional siloxane network [3][4][5]. The resulting matrix has high surface area, porosity, inertness, and stability to chemical and physical agents, and optical clarity in the visible and UV ranges [6][7][8].…”