Entrapment of biomolecules in sol–gel matrix for applications in biosensors: Problems and future prospects

An emerging area that has attracted increased attention in recent years is the development of biosensors based on sol–gel-derived platforms which must be predicated on an understanding of the short and long-term interactions between the biorecognition elements and evolving sol–gel matrix. This review focuses on the growing field of entrapment of biomolecules such as proteins, enzymes and antibodies in sol–gel matrices prepared from alkoxide precursors. Basic aspects of sol–gel, its advantages and disadvantages, factor affecting the sol–gel-derived thin films, strategies for improving entrapment of biomolecules in sol–gel materials and their organic modifications are discussed. Organically modified silane precursors have the ability to tune physical and chemical properties with desired characteristics of sol–gel preparations by simply changing different precursors and their molar ratio. The usefulness of optical method especially time-resolved fluorescence spectroscopy for the characterization of internal environment of sol–gel as well as dynamics of proteins within the sol–gel is highlighted. Significance and designing of new biocompatible sol–gel precursors with the purpose of making the glassy matrix more compatible with entrapped biomolecules has been described. Considerable attention has been drawn on problems and future prospects of sol–gel matrix for entrapment of biomolecules for applications in biosensors.