Development of Biocompatible Matrices for Whole Cell Biosensors

M. F. DESIMONE; G. S. ALVAREZ; M. L. FOGLIA; G. J. COPELLO; L. E. DÍAZ

Advances in Materials Science Research. Volume 2

Nova Science Publishers, Inc

Año: 2010; p. 1 - 27

  A biosensor is an analytical device that combines a biological sensing element with a transducer to produce a signal proportional to the analyte concentration. Microorganisms have been integrated with a variety of transducers such as amperometric, potentiometric, conductimetric, colorimetric, luminescent and fluorescent to construct biosensor devices. In this sense, a crucial parameter influencing the performance of biosensors is the protocol used for cell immobilization. During the last 20 years the sol-gel process has been used to efficiently immobilize whole living cells in inorganic and hybrid materials. High activity and longevity of cells entrapped in silica were demonstrated, which has several benefits for whole-cell biosensor applications. These matrices have some disadvantages due to their inorganic constitution, such as time dependent gel shrinkage, which induces pressure over the entrapped cells hence disturbing cell viability. On the other side, organic gels composed of agar, agarose or calcium alginate have been assayed and the effects of these immobilization methods on the stability of microbial cells were reported. It is well known, that organic materials have poor mechanical strength, long-term instability and more susceptibility to microbial attack and contamination. In between inorganic and organic gels we can find hybrid materials, which are being recently studied for its beneficial mechanical properties, among which they offer better water retention and membrane stabilizing capacities. This chapter reviews some of the major developments in the whole cell biosensor field involving immobilization matrices, cells employed as recognition elements and biosensor analytical performance.