Abstract
Colorimetric analysis has become of great importance in recent years to improve the operationalization of plasmonic-based biosensors. The unique properties of nanomaterials have enabled the development of a variety of plasmonics applications on the basis of the colorimetric sensing provided by metal nanoparticles. In particular, the extinction of localized surface plasmon resonance (LSPR) in the visible range has permitted the exploitation of LSPR colorimetric-based biosensors as powerful tools for clinical diagnostics and drug monitoring. This review summarizes recent progress in the biochemical monitoring of clinical biomarkers by ultrasensitive plasmonic colorimetric strategies according to the distance- or the morphology/size-dependent sensing modes. The potential of colorimetric nanosensors as point of care devices from the perspective of naked-eye detection is comprehensively discussed for a broad range of analytes including pharmaceuticals, proteins, carbohydrates, nucleic acids, bacteria, and viruses such as Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). The practical suitability of plasmonic-based colorimetric assays for the rapid visual readout in biological samples, considering current challenges and future perspectives, is also reviewed.
Highlights
The search for rapid disease diagnostic technologies has prompted the development of a great number of in vitro diagnostic methods relying on both laboratory-based analysis and near-patient testing [1]
point of care testing (POCT) has been commonly exploited for molecular diagnostics by electrochemical biosensors and lateral flow assays (LFAs) [11,12]
The distance-dependent color change strategy takes advantage of the cross-linking assembly effect resulting from the aggregation of nearby nanoparticles, whereas the latter one depends on the growth and etching processes caused by the modulation of the dimension and dielectric environment of metal nanoparticles (Figure 2) [14,15,16]
Summary
The search for rapid disease diagnostic technologies has prompted the development of a great number of in vitro diagnostic methods (over 40,000 products) relying on both laboratory-based analysis and near-patient testing [1]. The distance-dependent color change strategy takes advantage of the cross-linking assembly effect resulting from the aggregation of nearby nanoparticles, whereas the latter one depends on the growth and etching processes caused by the modulation of the dimension and dielectric environment of metal nanoparticles (Figure 2) [14,15,16] Both nanomaterials-based colorimetric approaches have been exploited to monitor chemical or biological species [34], including anions [38], metal ions [39,40], proteins [41], DNA [25], and organic molecules such as glucose [42,43]. Latest advances in the development of new colorimetric sensing mechanisms rendering promising diagnostic POC tools for the monitoring of molecular responses by visual inspection are reviewed
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