Determining the Nutrient Content of Hydroponically-Cultivated Microgreens with Immersible Silicon Photonic Sensors: A Preliminary Feasibility Study.

Microgreens have gained attention for their exceptional culinary characteristics and high nutritional value. The present study focused on a novel approach for investigating the easy extraction of plant samples and the utilization of immersible silicon photonic sensors to determine, on the spot, the nutrient content of microgreens and their optimum time of harvest. For the first time, it was examined how these novel sensors can capture time-shifting spectra caused by the molecules' dynamic adhesion onto the sensor surface.

Directly immersible silicon photonic probes: Application to rapid SARS-CoV-2 serological testing.

Silicon photonic probes based on broad-band Mach-Zehnder interferometry are explored for the first time as directly immersible immunosensors alleviating the need for microfluidics and pumps. Each probe includes two U-shaped waveguides allowing light in- and out-coupling from the same chip side through a bifurcated fiber and a mechanical coupler. At the opposite chip side, two Mach-Zehnder interferometers (MZI) are located enabling real-time monitoring of binding reactions by immersion of this chip side into a sample.

Fast label-free detection of C-reactive protein using broad-band Mach-Zehnder interferometers integrated on silicon chips.

An immunosensor for fast and accurate determination of C-reactive protein (CRP) in human serum samples based on an array of all-silicon broad-band Mach-Zehnder interferometers (BB-MZIs) is demonstrated. The detection was based on monitoring the spectral shifts during the binding of CRP on the antibody molecules that have been immobilized on the sensing arms of the BB-MZIs. By employing the reaction rate as the analytical signal the assay time was compressed to few minutes.

Detection of ochratoxin A in beer samples with a label-free monolithically integrated optoelectronic biosensor.

An optical biosensor for label-free detection of ochratoxin A (OTA) in beer samples is presented. The biosensor consists of an array of ten Mach-Zehnder interferometers (MZIs) monolithically integrated along with their respective broad-band silicon light sources on the same Si chip (37mm). The chip was transformed to biosensor by functionalizing the MZIs sensing arms with an OTA-ovalbumin conjugate.

Assessment of goat milk adulteration with a label-free monolithically integrated optoelectronic biosensor.

The label-free detection of bovine milk in goat milk through a miniaturized optical biosensor is presented. The biosensor consists of ten planar silicon nitride waveguide Broad-Band Mach-Zehnder interferometers (BB-MZIs) monolithically integrated and self-aligned with their respective silicon LEDs on the same Si chip. The BB-MZIs were transformed to biosensing transducers by functionalizing their sensing arm with bovine k-casein.