Label-Free Microcavity Biosensors: Steps towards Personalized Medicine

Abstract

Personalized medicine has the potential to improve our ability to maintain health and treat disease, while ameliorating continuously rising healthcare costs. Translation of basic research findings to clinical applications within regulatory compliance is required for personalized medicine to become the new foundation for practice of medicine. Deploying even a few of the thousands of potential diagnostic biomarkers identified each year as part of personalized treatment workflows requires clinically efficient biosensor technologies to monitor multiple biomarkers in patients in real time. This paper discusses a critical component of a regulatory system, a microcavity optical biosensor for label-free monitoring of biomolecular interactions at physiologically-relevant concentrations. While most current biosensor research focuses on improving sensitivity, this paper emphasizes other characteristics a biosensor technology requires to be practical in a clinical setting, presenting robust microcavity biosensors which are easy to manufacture and integrate with microfluidics into flexible and redesignable platforms making the microcavity biosensors deployable for continuous monitoring of biomarkers in body fluids in the clinic, in dense 2D random arrays for high-throughput applications like drug-library screening in interactomics, and of the secretory behavior of single cells in the laboratory.

Underlying Subwavelength Aperture Architecture Drives the Optical Properties of Microcavity Surface Plasmon Resonance Sensors

“…For a curvature radius of they find a transmission of about . Using a linear extrapolation of their findings down to radius, we estimate a transmission of about , which is consistent with our earlier experimental findings [ 28 ]. The MSPRS light intensity with respect to incident light intensity is estimated at [ 28 ] (p. 17277).…”

“…While illuminated with white light from above, the MSPRS emitted light was collected from below and spectrally analyzed. The following protocols are an updated version of previously used protocols [ 28 ]. Figure 1 a–i show the main steps in MSPRS chip fabrication.…”

“…However, this SPR canon builds a much-idealized model that comes in conflict with our understanding of more complex plasmonic structures such as the MSPRS presented in this paper [ 26 , 27 , 28 , 36 ]. For example, changes in the excitation method or the film thickness turn different results.…”

“…Li et al excite multiple SSPWs on 1-arm (I-shape), 2-arm (L-shape), and 3-arm (Z-shape) Ag nano-rods and correlate the length of the resonator to SSPW wavelengths [ 25 ]. To date, these works were most influential in understanding the physics governing microcavity surface plasmon resonance sensors (MSPRSs) [ 26 , 27 , 28 ].…”

“…MSPRS is an attractive sensor for several chief attributes. Firstly, MSPRS has about one micron footprint, thus making it a prime candidate for lab-on-a-chip sensing applications as it integrates with microfluidics devices [ 28 ]. Secondly, MSPRS is comparable in size with cells or bacteria.…”