8 - Biological recognition elements

Abstract

Biosensors are promising diagnostic tools that can be employed for point-of-care diagnostics at the bedside. In this time of the coronavirus pandemic, the whole world is looking for a rapid, sensitive, specific, and reliable test to put a check on the spread of infection. The development of a biosensor for COVID-19 detection can also provide a promising tool for the rapid screening of suspected patients and community surveillance. A biological recognition element (BRE) is an important component of a biosensor that provides a site for specific attachment of a particular analyte. A biological recognition element is a biomolecule or a fraction of a molecule, and the selection of an appropriate biological recognition element is the most crucial step in research, fabrication, and application of biosensors under field conditions. Although the first biosensor was discovered nearly 58years ago, tremendous progress has been made to fabricate different types of biosensors for the detection of pathogenic bacteria, viruses, fungi, environmental pollutants, allergens, toxins, etc. A biological recognition element, which is the key to the development of a biosensor, may be categorized as conventional or synthetic. Conventional biological recognition elements that include antibodies and enzymes are very commonly used nowadays for the fabrication of biosensors. Synthetic recognition elements include oligonucleotides, peptide nucleic acids, locked nucleic acids, aptamers, G-quadraplexes, molecularly imprinted polymers, etc. Modern biotechnology and genetic engineering tools have enabled us to develop recombinant biological recognition elements in vitro. The research and development in nanotechnology have opened up a large path for in vivo biosensors. These advances have paved the way for the generation of BREs other than those available in nature with high affinity. In this chapter, molecular recognition elements, their features, and their effects on fabrication have been summarized.