Emerging applications of label-free optical biosensors

Abstract

Abstract:Innovative technical solutions to realize optical biosensors with improved performance are continuously proposed. Progress in material fabrication enables developing novel substrates with enhanced optical responses. At the same time, the increased spectrum of available biomolecular tools, ranging from highly specific receptors to engineered bioconjugated polymers, facilitates the preparation of sensing surfaces with controlled functionality. What remains often unclear is to which extent this continuous innovation provides effective breakthroughs for specific applications. In this review, we address this challenging question for the class of label-free optical biosensors, which can provide a direct signal upon molecular binding without using secondary probes. Label-free biosensors have become a consolidated approach for the characterization and screening of molecular interactions in research laboratories. However, in the last decade, several examples of other applications with high potential impact have been proposed. We review the recent advances in label-free optical biosensing technology by focusing on the potential competitive advantage provided in selected emerging applications, grouped on the basis of the target type. In particular, direct and real-time detection allows the development of simpler, compact, and rapid analytical methods for different kinds of targets, from proteins to DNA and viruses. The lack of secondary interactions facilitates the binding of small-molecule targets and minimizes the perturbation in single-molecule detection. Moreover, the intrinsic versatility of label-free sensing makes it an ideal platform to be integrated with biomolecular machinery with innovative functionality, as in case of the molecular tools provided by DNA nanotechnology.

Disposable Sensors in Diagnostics, Food, and Environmental Monitoring

“…The optical signal produced may be observed by the naked eye or measured by a photodetector. Photodetectors (devices that convert optical signals into measurable electrical signals) are categorized into thermal (thermopiles) and photon detectors (photodiodes or photomultipliers) …”

Critical assessment of relevant methods in the field of biosensors with direct optical detection based on fibers and waveguides using plasmonic, resonance, and interference effects

“…Progress in material fabrication and novel substrate with enhanced optical response properties and potential application for rapid analytical measurement of target interactions from proteins to DNA and viruses are demonstrated in a review article on emerging applications [113]. Looking especially at small molecules, many techniques, including surfaceenhanced Raman spectroscopy, have been reviewed in a recent article, together with potential evaluation techniques [114].…”

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