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Journal of Nanophotonics • Open Access

Label-free photonic biosensors fabricated with low-loss hydrogenated amorphous silicon resonators
Author(s): Timo Lipka; Lennart Wahn; Hoc-Khiem Trieu; Lutz Hilterhaus; Jorg Muller

Paper Abstract

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, and low-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.

Paper Details

Date Published: 5 November 2013
PDF: 11 pages
J. Nanophoton. 7(1) 073793 doi: 10.1117/1.JNP.7.073793
Published in: Journal of Nanophotonics Volume 7, Issue 1
Show Author Affiliations
Timo Lipka, Technische Univ. Hamburg-Harburg (Germany)
Lennart Wahn, Technische Univ. Hamburg-Harburg (Germany)
Hoc-Khiem Trieu, Technische Univ. Hamburg-Harburg (Germany)
Lutz Hilterhaus, Technische Univ. Hamburg-Harburg (Germany)
Jorg Muller, Technische Univ. Hamburg-Harburg (Germany)

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