Dataset Information

Greatly Enhanced Single Particle Fluorescence Detection Using High Refractive Index Liquid-Core Waveguides.

ABSTRACT: High sensitivity and easy integration with microfabrication techniques has made silicon photonics one of the leading technologies used to build biosensors for diagnostic applications. Here we introduce a new silicon dioxide based optofluidic platform having a planar solid-core (SC) waveguide orthogonally intersecting a liquid-core (LC) waveguide with high refractive index ZnI2 salt solution as core. This enables both more uniform collection of particle fluorescence by the core mode and its propagation to an off-chip detector. This approach results in ultra-high sensitivity performance, demonstrated by achieving 8X enhancement in signal-to-noise ratio, a 45x increase in detection efficiency, and a 100x lower detection limit of 80 aM of fluorescent nanobeads. This represents a key step towards an ultrasensitive biosensor system for analyzing pathogens at clinical concentrations.

SUBMITTER: Meena GG

PROVIDER: S-EPMC8117828 | biostudies-literature | 2021 Sep-Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Greatly Enhanced Single Particle Fluorescence Detection Using High Refractive Index Liquid-Core Waveguides.

Meena Gopikrishnan Gopalakrishnan GG Wright Joel G JG Hawkins Aaron R AR Schmidt Holger H

IEEE journal of selected topics in quantum electronics : a publication of the IEEE Lasers and Electro-optics Society 20210128 5

High sensitivity and easy integration with microfabrication techniques has made silicon photonics one of the leading technologies used to build biosensors for diagnostic applications. Here we introduce a new silicon dioxide based optofluidic platform having a planar solid-core (SC) waveguide orthogonally intersecting a liquid-core (LC) waveguide with high refractive index ZnI2 salt solution as core. This enables both more uniform collection of particle fluorescence by the core mode and its propa ...[more]

PMID: 33994767

Similar Datasets

Project description:Refractive index-based sensors offer attractive characteristics as nondestructive and universal detectors for liquid chromatographic separations, but a small dynamic range and sensitivity to minor thermal perturbations limit the utility of commercial RI detectors for many potential applications, especially those requiring the use of gradient elutions. As such, RI detectors find use almost exclusively in sample abundant, isocratic separations when interfaced with high-performance liquid chromatography. Silicon photonic microring resonators are refractive index-sensitive optical devices that feature good sensitivity and tremendous dynamic range. The large dynamic range of microring resonators allows the sensors to function across a wide spectrum of refractive indices, such as that encountered when moving from an aqueous to organic mobile phase during a gradient elution, a key analytical advantage not supported in commercial RI detectors. Microrings are easily configured into sensor arrays, and chip-integrated control microrings enable real-time corrections of thermal drift. Thermal controls allow for analyses at any temperature and, in the absence of rigorous temperature control, obviates extended detector equilibration wait times. Herein, proof of concept isocratic and gradient elution separations were performed using well-characterized model analytes (e.g., caffeine, ibuprofen) in both neat buffer and more complex sample matrices. These experiments demonstrate the ability of microring arrays to perform isocratic and gradient elutions under ambient conditions, avoiding two major limitations of commercial RI-based detectors and maintaining comparable bulk RI sensitivity. Further benefit may be realized in the future through selective surface functionalization to impart degrees of postcolumn (bio)molecular specificity at the detection phase of a separation. The chip-based and microscale nature of microring resonators also make it an attractive potential detection technology that could be integrated within lab-on-a-chip and microfluidic separation devices.

Project description:We describe a hybrid metal-dielectric waveguide structures (MDWs) with numerous potential applications in the biosciences. These structures consist of a thin metal film coated with a dielectric layer. Depending on the thickness of the dielectric layer, the modes can be localized near the metal, within the dielectric, or at the top surface of the dielectric. The optical modes in a metal-dielectric waveguide can have either S (TE) or P (TM) polarization. The dielectric spacer avoids the quenching, which usually occurs for fluorophores within about 5 nm from the metal. Additionally, the resonances display a sharp angular dependence and can exhibit several hundred-fold increases in intensity (E2) at the silica-air interface relative to the incident intensity. Fluorophores placed on top of the silica layer couple efficiently with the metal, resulting in a sharp angular distribution of emission through the metal and down from the bottom of the structure. This coupling occurs over large distances to several hundred nm away from the metal and was found to be consistent with simulations of the reflectivity of the metal-dielectric waveguides. Remarkably, for some silica thicknesses, the emission is almost completely coupled through the structure with little free-space emission away from the metal-dielectric waveguide. The efficiency of fluorophore coupling is related to the quality of the resonant modes sustained by the metal-dielectric waveguide, resulting in coupling of most of the emission through the metal into the underlying glass substrates. Metal-dielectric waveguides also provide a method to resolve the emission from surface-bound fluorophores from the bulk-phase fluorophores. Metal-dielectric waveguides are simple to fabricate for large surface areas, the resonance wavelength can be adjusted by the dielectric thickness, and the silica surface is suitable for coupling to biomolecules. Metal-dielectric waveguides can have numerous applications in diagnostics and high-throughput proteomics or DNA analysis.

Dataset Information

Greatly Enhanced Single Particle Fluorescence Detection Using High Refractive Index Liquid-Core Waveguides.

Publications

Greatly Enhanced Single Particle Fluorescence Detection Using High Refractive Index Liquid-Core Waveguides.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets