Advances in Affinity-Based Biosensing Mechanisms for Direct Detection/Monitoring of the Biomarkers

Biomarkers offer valuable insights into numerous diseases, making it imperative to establish an analytical systems. For the detection and monitoring of these biomarkers from various biofluids such as urine, serum, blood, saliva, sweat, and interstitial fluid. Presently, the analysis of these biomarkers is primarily conducted using sophisticated instruments including chromatographs and spectroscopes. Despite their excellent analytical performance, the turnaround time and easy access are restricted in ambulatory, remote, and bedside settings. Over the past decade, biosensing methodologies have made significant advancements, offering point-of-care sensing, miniaturized instrumentations, and mobile/personalized monitoring systems. These operate on catalytic and affinity-based biosensing principles leveraging numerous biosensors. While the catalytic sensors have a limited number of biomarkers restricted only to the metabolites and electroactive species, affinity-based sensing exploits the biological interactions such as antibody-antigen, and receptor-ligands coupling, eventually leveraging the flexibility toward the development of enormous sensors. This chapter discusses the fundamental mechanisms and recent advancements in affinity-based sensing techniques used to detect or continuously monitor a wide range of biomarkers. The primary focus of the discussion has been on the fabrication protocols, benefits, and drawbacks of affinity-based sensing systems, as well as various optical and electrochemical transduction techniques that have been utilized.