On-chip integration of plasmonics and electronics can benefit a broad range of applications in biosensing, signal processing, and optoelectronics. A key requirement is a chip-scale manufacturing method. Here, we demonstrate a split-trench resonator platform that combines a high-quality-factor resonant plasmonic biosensor with radio frequency (RF) nanogap tweezers. The split-trench resonator can simultaneously serve as a dielectrophoretic trap and a nanoplasmonic sensor. Trapping is accomplished by applying an RF electrical bias across a 10 nm gap, thereby either attracting or repelling analytes. Trapped analytes are detected in a label-free manner using refractive-index sensing, enabled by interference between surface-plasmon standing waves in the trench and light transmitted through the gap. This active sample concentration mechanism enables detection of nanoparticles and proteins at a concentration as low as 10 pM. We can manufacture centimeter-long split-trench cavity resonators with high throughput via photolithography and atomic layer deposition, toward practical applications in biosensing, spectroscopy, and optoelectronics.
Bibliographical noteFunding Information:
D.Y., A.B., D.A.M., and S.-H.O. acknowledge support from the U.S. National Science Foundation (NSF ECCS 1809723 and ECCS 1809240). D.Y. and S.-H.O. acknowledge partial support provided by the Minnesota Environment and Natural Resources Trust Fund as recommended by the Legislative-Citizen Commission on Minnesota Resources (LCCMR). F.d.L.P. and L.M.-M. acknowledge financial support from Spanish Ministry of Economy and Competitivity through projects MAT2017-88358-C3-1-R and MAT2017-88358-C3-2-R and the Aragón Government project Q-MAD. M.P. acknowledges support from the U.S. National Science Foundation (NSF DMR-1905135). S.-H.O. further acknowledges support from the Sanford P. Bordeau Endowed Chair at the University of Minnesota and the McKnight Foundation.
© 2021 American Chemical Society.
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