Analyte-Gated Plasmonic Hot-Carrier Current for Ultrasensitive Biosensing

초록

We report the first optoelectronic biosensor that employs plasmonic hot carriers for signal transduction. Hot-carrier generation and transfer were driven by plasmonic hot spots formed through biomarker-mediated attachment of gold nanoparticles to a gold film. As proof of concept, a device was developed for quantitative detection of 17 beta-estradiol (E2), a key biomarker for early diagnosis of precocious puberty in pediatric patients. The sensor enabled ultrasensitive detection of trace E2, even in human urine, with a limit of detection of approximate to 13 aM (3.5 ag/mL), to the best of our knowledge, the lowest reported to date. In contrast to conventional plasmonic biosensors based on local refractive index change, which are inherently limited for low-molecular-weight analytes, this platform uses plasmon-generated hot carriers and thus achieves ultrahigh sensitivity for small molecules such as E2 (approximate to 272 Da). These results establish plasmonic hot carriers as a promising transduction mechanism for scalable and multiplexed bio- and chemical sensing platforms.

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