Sensitivity‐Enhancing Strategies in Optical Biosensing

Abstract

High‐sensitivity detection of minute quantities or concentration variations of analytes of clinical importance is critical for biosensing to ensure accurate disease diagnostics and reliable health monitoring. A variety of sensitivity‐improving concepts have been proposed from chemical, physical, and biological perspectives. In this review, elements that are responsible for sensitivity enhancement are classified and discussed in accordance with their operating steps in a typical biosensing workflow that runs through sampling, analyte recognition, and signal transduction. With a focus on optical biosensing, exemplary sensitivity‐improving strategies are introduced, which can be developed into “plug‐and‐play” modules for many current and future sensors, and discuss their mechanisms to enhance biosensing performance. Three major strategies are covered: i) amplification of signal transduction by polymerization and nanocatalysts, ii) diffusion‐limit‐breaking systems for enhancing sensor–analyte contact and subsequent analyte recognition by fluid‐mixing and analyte‐concentrating, and iii) combined approaches that utilize renal concentration at the sampling and recognition steps and chemical signal amplification at the signal transduction step.

Recent advances in fluorescence anisotropy/polarization signal amplification

“…However, as they can be denatured and digested by proteases easily, it is hard to operate them in complex biological samples. 100,101 Enzyme-free signal amplification strategies based on toehold-mediated DNA strand displacement have been developed to amplify FA/FP signal, which works under mild conditions without specific demand for either ionic strength or temperature comparing with enzyme amplification. Tan group reported a target-triggered assembly approach based on the formation of DNA–protein hybrid nanowires via HCR, using ATP as a small molecule model.…”

Multiplex Chroma Response Wearable Hydrogel Patch: Visual Monitoring of Urea in Body Fluids for Health Prognosis

“…28−33 Among them, colorimetric and fluorescence methods have better selectivity and are suitable for achieving detection of targets in complex detection environments of biological samples. 34 The colorimetric method is susceptible to interference from ambient light and skin tones when used as wearable sensors, and the fluorescence method possesses higher sensitivity while overcoming these drawbacks. 35 However, most of the currently reported fluorescent hydrogels are excited by short wavelengths and are susceptible to interference from autofluorescence and background fluorescence when detecting biological samples.…”

“…The increasing demand for monitoring individual health indicators has driven the development of various biosensor devices. In recent years, wearable sensors have attracted wide attention due to their ability to be worn directly on human skin, biocompatibility, and non-invasiveness. − To date, various wearable sensors have been reported for detecting human motion and physiological signals, such as joint activity, blood pressure, body temperature, blood oxygen, and pH. − Hydrogels with three-dimensional network-like structures are an ideal material as wearable sensors due to their good flexibility, stretchability, and biocompatibility. − They can respond to external physical and chemical stimuli through sensing strategies such as surface plasmon resonance, colorimetric, fluorescence, and electrochemical. − Among them, colorimetric and fluorescence methods have better selectivity and are suitable for achieving detection of targets in complex detection environments of biological samples . The colorimetric method is susceptible to interference from ambient light and skin tones when used as wearable sensors, and the fluorescence method possesses higher sensitivity while overcoming these drawbacks .…”

A biosensor encompassing fusarinine C-magnetic nanoparticles and aptamer-red/green carbon dots for dual-channel fluorescent and RGB discrimination ofCampylobacterandAliarcobacter

“…This signal can be further read and recorded with a processing apparatus [18]. To be noted, within those optical sensing methodologies, fluorescence is particularly promising due to its high sensitivity, facile manipulation and ability to indicate analytes with low abundance [20]. Dual-channel fluorescent detection [21,22] has value for the simultaneous sensing of two bacteria.…”