Colorimetric Biosensors for Rapid Biological Detection: Principles, Nanomaterial Advances, Portable Platforms, and Challenges

Abstract

Colorimetric biosensors offer the advantages of being simple, low cost, portable and the response being visually interpretable, and have thus become potential platforms for rapid, biological detection without the need for complex laboratory instrumentation. In this review, recent progress in colorimetric biosensing is discussed, focusing on the principles and mechanisms behind colour generation, such as localized surface plasmon resonance, aggregation of nanoparticles, enzymatic reactions, and nanozyme-catalysis. Enhance analytical signals by nanomaterials, especially by the use of nanoparticles of noble metals, nanozymes and advanced nanostructures, is discussed. Recent developments on paper-based platforms, as well as smartphone-assisted colour analysis, are also emphasized for point-of-care and decentralised testing. Applications included pathogen, nucleic-acid, protein, biomarker, food, and environmental detection, highlighting the wide range of system applications. But there are still problems concerning sensitivity, colour interpretation, biological interference, nanomaterial reproducibility, quantitative analysis, standardization, and real world validation. The practical application of colorimetric biosensors can be further enhanced by further integration with nanotechnology, digital imaging, and portable platforms.