title: Label-free biosensor based on an electrical tracing-assisted silicon microring resonator with a low-cost broadband source.
abstract: We present a novel biosensor based on an electrical tracing-assisted silicon dual-microring resonator sensor system. The dual-microring system comprises one microring resonator as a sensing element and the other microring resonator integrated with an electrical controller as a tracing element. The resonance wavelength shift of the sensing microring induced by the refractive index change due to antigen-ligand bindings is traced and determined by direct voltage applied to the electrical tunable tracing microring. The sensor system enables the use of a low-cost broadband light source instead of a bulky and expensive tunable laser, which allows the development of cost-effective point-of-care diagnostic devices by significantly reducing the device cost and increasing its portability. The sensing capability of the developed dual-microring sensor was investigated using biotin-streptavidin binding as a model system. We have demonstrated the quantitative detection of streptavidin over a broad range of concentrations down to 190 pM by monitoring the electrical power applied to the tracing ring. We have also validated the sensing principle of the dual-microring system by a direct comparison between the calculated and measured values for the resonance wavelength shift of the sensing microring. Furthermore, we have shown the quantitative and specific detection of a well-known breast cancer biomarker, human epidermal growth factor receptor 2 (HER2), in a bovine serum albumin solution using the antibody-modified dual-microring sensor system.
authors.affiliation: Institute of Microelectronics, A*STAR (Agency for Science, Technology and Research), 11 Science Park Road, Singapore Science Park II, Singapore 117685, Singapore.
authors.forename: Kyung Woo
authors.initials: KW
authors.lastname: Kim
authors.forename: Junfeng
authors.initials: J
authors.lastname: Song
authors.forename: Jack Sheng
authors.initials: JS
authors.lastname: Kee
authors.forename: Qing
authors.initials: Q
authors.lastname: Liu
authors.forename: Guo-Qiang
authors.initials: GQ
authors.lastname: Lo
authors.forename: Mi Kyoung
authors.initials: MK
authors.lastname: Park
mesh_terms: D000818:Animals; D055910:Antibodies, Immobilized / Q000737:chemistry; D015374:Biosensing Techniques / Q000191:economics / Q000295:instrumentation*; D004867:Equipment Design; D006801:Humans; D008027:Light; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis*; D012031:Refractometry / Q000191:economics / Q000295:instrumentation; D012680:Sensitivity and Specificity; D012825:Silicon / Q000737:chemistry*; D019809:Streptavidin / Q000032:analysis*
chemical_list: D055910:Antibodies, Immobilized; D018719:Erb-b2 Receptor Tyrosine Kinases; D012825:Silicon; D019809:Streptavidin; C508053:ERBB2 protein, human