Nanophotonics and Plasmonics

Marine photosynthetic microorganisms are responsible for over half of the oxygen on earth and are key to our carbon cycle. But, under certain conditions, phytoplankton can form dense blooms that release powerful biotoxins that contaminate drinking water sources. Correlating how environmental drivers drive toxin production during harmful algae blooms remains a key challenge due to the constraints of extending dominant lab techniques, like mass spectroscopy and DNA sequencing, to remote marine environments. Recent advances in autonomous underwater vehicles (AUVs) are enabling in situ marine measurements of temperature, pH, and fluorescence. Similar measurements of small molecule metabolites and nucleotides are critical to understanding fundamental marine metabolic cycling but current sensors are limited by low sensitivity, dynamic range, and scalability.  Here, we present an approach based on silicon nanophotonics to simultaneously and rapidly measure multiple ‘omic’ signatures from phytoplankton in aquatic samples. Our high-quality metasurfaces are composed of subwavelength silicon nanoblocks that resonantly trap and strongly amplify the electromagnetic field intensity in a 15 micron optical antenna . Thousands of resonator pixels can be fabricated as individually addressable elements and read out simultaneously on a simple CCD array. Molecular binding through self-assembled monolayers generates small perturbations to the local dielectric environment, strongly shifting the optical resonance. Molecular binding generates small perturbations to the local dielectric environment, strongly shifting the optical resonance. We use this platform to demonstrate quantitative and amplification-free sub-picomolar detection of DNA and the harmful algae bloom toxin, microcystin, which pose a threat to drinking water supplies. Finally, we will discuss the integration of our high-Q metasurfaces with the Environmental Sample Processor (ESP), an autonomous robotic water processor developed at the Monterey Bay Aquarium Research Institute (MBARI), offering a pathway for in situ multi-omic detection, processing, and analysis.