Label-free photonic biosensors fabricated with low-loss hydrogenated amorphous silicon resonators

The precise detection of chemicals and biomolecules is of great interest in the areas of biotechnology and medical diagnostics. Thus, there is a need for highly sensitive, small area, andlow-cost sensors. We fabricated and optically characterized hydrogenated amorphous silicon photonic resonators for label-free lab-on-chip biosensors. The sensing was performed with small-footprint microdisk and microring resonators that detect a refractive-index change via the evanescent electric field. Homogeneous sensing with NaCl and surface-sensing experiments with immobilized bovine serum albumin (BSA) were carried out. A sensitivity as high as 460 nm/RIU was measured for NaCl dissolved in deionized water for the disk, whereas about 50 nm/RIU was determined for the ring resonator. The intrinsic limits of detection were calculated to be 3.3 × 10-4 and 3.2 × 10-3 at 1550-nm wavelength. We measured the binding of BSA to functionalized ring resonators and found that molecular masses can be detected down to the clinically relevant femtogram regime. The detection and quantification of related analytes with hydrogenated amorphous silicon photonic sensors can be used in medical healthcare diagnostics like point-of-care-testing and biotechnological screening.

Schlagworte

amorphous silicon

a-Si

H

photonics

microring

microdisk

resonator

label-free biosensor

lab-on-chip

point-of-care diagnostics

DDC Class

530: Physik

570: Biowissenschaften, Biologie

Projekt(e)

Biosensor auf Basis integrierter Photonik

Publication version

publishedVersion

Lizenz

https://creativecommons.org/licenses/by/3.0/

Name

073793_1.pdf

Size

3.03 MB

Format

Adobe PDF

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Label-free photonic biosensors fabricated with low-loss hydrogenated amorphous silicon resonators