Optical microarray biosensing techniques

Abstract

Microarrays provide a powerful analytical tool for the simultaneous analyses of thousands of parameters, be they DNA or proteins, in a single experiment. However, a number of challenges continue to hinder the widespread application of microarray assays for analytical and diagnostic purposes. Advances in detection methods can help overcome some of these challenges by improving sensitivity and reliability in signal detection and by enabling real-time detection of binding events. Thus, the aim of this review is to highlight the most promising optical microarray biosensing techniques. The principles of techniques making use of labels, including scanner type, total internal reflection type, fiber-optics-based, and SPRenhanced fluorescence, are described, along with a brief summary of labeling strategies. State of the art label-free techniques, including imaging SPR and imaging ellipsometry, are also reviewed. Examples of microarray-based assays using each technique are given to illustrate both their usefulness and their limits of detection. Furthermore, the most competitive commercial microarray systems are presented and compared with one another in the context of their detection system. Finally, a discussion of the remaining challenges as well as trends and future applications of microarrays are presented in the context of optical sensing.

Tunable Nanowrinkles on Shape Memory Polymer Sheets

“…One potential MEF application is to improve the sensitivity of DNA and protein microarrays, in which high density probes with spot sizes from 10 to 500 mm are immobilized on substrates with areas of several square centimeters. [35] Fluorescence is widely adopted for detection owing to its ultrahigh sensitivity and capabilities for multiple-probe labeling. Recently, use of SPR to lower the detection limit has become desirable to broaden its applications.…”

“…Recently, use of SPR to lower the detection limit has become desirable to broaden its applications. [35] To integrate our plasmonic material into commercial products, we demonstrated that our wrinkles can be easily patterned. In Figure 3e, discrete ''wrinkled flowers'' with diameters around 50 mm are shown to be well aligned.…”

Controllable Cobalt Oxide/Au Hierarchically Nanostructured Electrode for Nonenzymatic Glucose Sensing

“…It is known that SERS has equal or in some cases a greater enhancement of Raman signal when compared to fluorescent markers and that SERS metal substrates produce spectral line widths which are 10-100 times narrower compared to fluorescence [64,318,319]. This means the technique can be used where high selectivity and multiplexing (targeting two analytes at once) is called for since the resolution between peaks will be well defined [320][321][322][323][324][325][326][327][328][329][330][331][332]. In addition, the short Raman scattering lifetime prevents photobleaching and quenching [312,323,324].…”

“…Solution based immunoassays overcome the slow diffusion kinetics and poor limit of detection (LOD) associated with conventional assays [73,319,320]. For example, the lung cancer carcinoembryonic antigen (CEA) was targeted using HGNs as a probe [325].…”

Protein microarray biosensors based on imaging ellipsometry techniques and their applications

“…Similar to genome research, studying the characteristics of protein-protein interactions requires the ability to perform massively parallel analyses (Yu et al, 2006). Microarray technology is a promising method to provide an effective solution for simultaneous detection of various analytes in a single experiment (Bally et al, 2006). Microarrays are built by assembling a set of ligands onto a solid surface and are suitable for high-throughput analyses.…”