Optical Resonator Biosensors: Molecular Diagnostic and Nanoparticle Detection on an Integrated Platform

Abstract

Optical resonator biosensors are emerging as one of the most sensitive microsystem biodetection technology that does not require amplification or labeling of the analyte. This minireview provides a scholarly introduction to this research area and reviews current advances in molecular diagnostics and nanoparticle detection.

Ultrasensitive detection of a protein by optical trapping in a photonic‐plasmonic microcavity

“…Protein detection with plasmon-coupled microcavity biosensor [5,6], optical sensors such as Raman spectroscopy [7][8][9][10][11], plasmon resonance [12] and emerging Whispering Gallery Mode (WGM) [13][14][15][16][17][18] sensors have been utilized for detecting biomolecules at mg-ng/ml sensitivity levels. WGM biosensing offers a particularly sensitive approach to quantify the mass loading of biomolecules on the resonator surface with ultimate sensitivity estimated on the single molecule level [19,20].…”

“…Achieving the goal of single molecule detection of proteins ($10 nm in size) and their actions in solution requires mechanisms for boosting sensitivity in WGM biosensing [13]. Several approaches have been investigated recently, and specific examples for enhancement mechanisms include the use of multiplexed sensor arrays [27], self-referenced mode-splitting techniques [25,26] as well as hybrid photonicplasmonic WGMs [29,30].…”

Taking detection to the limit with optical microcavities: Recent advances presented at the 560. WE Heraeus Seminar

“…Theories have been developed to quantitate the frequency shift signals, by tracking one or more WGMs during molecular interaction events, thereby determining the number of molecules bound to the microcavity, deduce their binding orientation, as well as determine the thickness of an adsorbed layer [2,31,34,[43][44][45][46][47][48]. These analysis have been extended to other resonator geometries such as liquid core ring resonators [47], and also many simulation and theoretical tools have been developed in this context [41,[49][50][51].…”

“…Binding of molecules at the microsphere surface causes the WGM resonance frequency to shift. The high Q factor results in a narrow linewidth which allows the detection of minute frequency shifts due to binding of nanoparticles or biomolecules [2][3][4][5][6], Fig. 1.…”

Sub-kHz lasing of a CaF_2 whispering gallery mode resonator stabilized fiber ring laser

“…Compact and tunable stable light sources are in high demand in metrology [1] and biochemical sensing [2,3] to mention just two predominant fields. Optical resonators are at the heart of narrow frequency light sources.…”