Label-Free Biosensors Based Onto Monolithically Integrated Onto Silicon Optical Transducers

Abstract

The article reviews the current status of label-free integrated optical sensors focusing on the evolution over the years of their analytical performance. At first a short introduction to the evanescent wave optics is provided followed by detailed description of the main categories of label-free optical sensors including sensors based on surface plasmon resonance (SPR), grating coupler, photonic crystals, ring resonators and interferometric transducers. After a short reference to SPR techniques, including localized SPR, integrated optical sensors i.e., grating-couplers, interferometers, photonic crystals, microring resonators are reviewed. For each type of sensor, the detection principle is first provided followed by description of the different transducer configurations so far developed and their performance as biosensors. Finally, a short discussion about the current limitations and future perspectives of integrated label-free biosensors optical sensors is provided

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

“…A similar field of optical methods (interferometers, waveguide sensors, and grating couplers) is reviewed in detail in [126]. Another recent review covers SPR, grating couplers, photonic crystals, ring resonators, and interferometers [410]. Fabry-Perot interferometric fiber-optic sensors are discussed with applications in [411].…”

Multiplexed Immunosensors and Immunoarrays

“…An optical biosensor chip was made for rapid, simultaneous detection of food allergens in bovine milk protein, peanut protein, soy protein, and gliadin. 106 The sensor chip consisted of monolithic silicon coupled with 10 broad-band Mach-Zehnder interferometers and broad band LED light sources. Interferometer surfaces were biofunctionalized to form a sandwich assay with the target antigen antibodies, antigens, and their corresponding antispeciesspecific antibodies.…”

“…An interferometric sensor chip featuring of 10 Mach-Zehnder interferometric sensor along with individual accompanying LED sources in a microfluidic device was developed for competitive protein immunoassays. 141 Transmission spectra were continuously recorded while flowing antibody-sample mixtures across standard protein spots. Data processing by Fourier transform analysis provided polarization phase shifts for each sensor.…”

Systematic comparison between photonic sensors based on dielectrics and metals

“…Even though some papers discuss characteristics of both plasmonic and dielectric systems [24], [36], [49], [54], it is usually difficult to find in the literature a standardized approach which discriminates the main features of these devices, because each group tends to use a different platform, thus hindering a comparative assessment of the devices.…”