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Abstract:

Over the past decades, there has been a remarkable progress in the field of biosensing technologies. Biosensors are analytical devices that use biological components for target recognition and subsequently convert this molecular event into a physically detectable signal. One type of biosensor became particularly appealing for studying biomolecular interactions, namely surface plasmon resonance (SPR) biosensor. This is one of the most advanced label free, real time detection technologies that provides information on quantification, but also on the kinetics of the binding reaction. Moreover, it can be used for studying a diverse set of interactions between proteins, lipids, nucleic acids, or low molecular weight molecules such as drugs. Because of these qualities, SPR-based biosensors are lately becoming a competitive tool for various applications in life science, food analysis, environmental monitoring, medical diagnostics and drug discovery. However, despite this, commercially available SPR biosensors cover only limited area of the biochemical monitoring market, because they have to compete with existing technologies on the basis of factors such as low cost, ease of use, robustness and sensitivity. Although lately there has been a constant technical improvement in generating and amplifying the SPR signal, most of the commercially available SPR platforms are still bulky instruments with expensive optical components. Our research group has developed an innovative fiber optic (FO) SPR platform that has a great potential for becoming applicable outside the specialized research environment due to several features. First, the FO-SPR sensor consists of a low-cost light source, a spectrophotometer, a bifurcated optical fiber, and sensor tips integrated on a robotic arm that allows their easy manipulation in a microplate format. As such, this platform has a capacity for multichannel performance needed for high-throughput screening applications. Furthermore, the detection limits of our biosensor, and thus its sensitivity, are improved by incorporating nanoparticles into bioassays, which is not feasible with traditional, microfluidics based SPR systems. We have also shown that the FO-SPR sensor can be applied in an automated setup for both protein- and DNA-based bioassays, making it thus useful for different applications. For example, the DNA amplification/melting processes can be monitored in real-time, which has not been accomplished before with commercial SPR setups as they do not allow for fast thermocycling. By exploiting this concept, we are able to screen for single nucleotide polymorphisms in real-time, which makes FO-SPR ideally suited for fast genetic screening of short fragments. Moreover, in various proof-of-concept studies the sensor was successfully applied for pathogen detection in food, paratuberculosis detection in cattle, and allergenicity screening in blood serum, demonstrating thus its great potential.