Fluorescence-Based Portable Assays for Detection of Biological and Chemical Analytes

Abstract

Fluorescence-based detection techniques are part of an ever-expanding field and are widely used in biomedical and environmental research as a biosensing tool. These techniques have high sensitivity, selectivity, and a short response time, making them a valuable tool for developing bio-chemical assays. The endpoint of these assays is defined by changes in fluorescence signal, in terms of its intensity, lifetime, and/or shift in spectrum, which is monitored using readout devices such as microscopes, fluorometers, and cytometers. However, these devices are often bulky, expensive, and require supervision to operate, which makes them inaccessible in resource-limited settings. To address these issues, significant effort has been directed towards integrating fluorescence-based assays into miniature platforms based on papers, hydrogels, and microfluidic devices, and to couple these assays with portable readout devices like smartphones and wearable optical sensors, thereby enabling point-of-care detection of bio-chemical analytes. This review highlights some of the recently developed portable fluorescence-based assays by discussing the design of fluorescent sensor molecules, their sensing strategy, and the fabrication of point-of-care devices.

A fluorescence viewer for rapid molecular assay readout in space and low-resource terrestrial environments

“…Their sensitivity and scalability-manifest in techniques like quantitative polymerase chain reaction (qPCR), loop-mediated isothermal amplification (LAMP), and enzyme-linked immunosorbent assay (ELISA)-have made them the frequent method of choice for detecting gene expression, protein activity, and various metabolites in samples of interest [1]. However, owing to high cost, complexity, and the requirement to operate within a centralized lab framework, state-of-the-art fluorescence-based assays have faced major barriers to adoption in field science and low-resource or disaster settings [2]. Similar hurdles are faced aboard the International Space Station (ISS), where gene expression studies are fundamentally limited by equipment availability and the need to return samples to Earth, forcing vibrational and temperature stresses from atmospheric re-entry to be introduced before data analysis [3].…”

Advances in Lensless Fluorescence Microscopy Design

“…This approach uses fluorescent markers that attach to certain cellular components to provide precise information about organelles [4][5][6]. Its ability to reveal the dynamic interactions within cells and between molecular constituents is invaluable, providing critical insights into biological functions and pathologies [7][8][9][10][11], and it is crucial in several different fields, including drug discovery, disease diagnostics, genetic research, oncology, and neuroscience, amongst others.…”