Phage Antibodies for Detection of Diagnostically Important Antigens

The need for rapid and cheap synthesis of large numbers of chemical compounds has contributed to the emergence of combinatorial chemistry (simultaneous synthesis of different compounds, in contrast to traditional synthesis, in which each substance is produced individually). Combinatorial library methods were initially applied only to peptides and oligonucleotides. By now, the scope of these libraries has expanded considerably to include proteins, synthetic oligomers, small molecules, and oligosaccharides. The enormous variety of antibodies (Abs) makes it possible to detect clones able to interact highly specifically with almost any natural or synthetic antigen (Ag). Phage Abs are an excellent alternative to mono- and polyclonal Abs, because they are highly stable, have no disulfide bonds, and are much cheaper to make. Monitoring of various substances, including proteins, in a living organism is much in demand. Despite the vast amount of literature available on Ab phage display, the use of phage display to determine diagnostically important Ags has not been sufficiently covered. Many studies have confirmed that unlike other types of Abs, phage Abs ensure highly sensitive Ag detection. Therefore, this review focuses on the use of phage display to prepare Abs specific to diagnostically important Ags (allergens, disease and cancer biomarkers, toxins) and on their application in analytical systems, including biosensors. The use of phage Abs in Ag diagnostics is compared with the use of classical Abs, and the prospects are shown for the use of phage Abs as biosensor sensing elements. This review analyzes the recent advances in the detection of diagnostically important Ags by using phage display-based biosensors. Systematic information is presented about allergens, disease and cancer biomarkers, and toxins detected by using phage Abs. Phage display Abs for sensor-based Ag detection are presented as an affordable alternative to classic tests.