CAREER: A portable nanosensor for ultrasensitive optical detection of airborne agents

University Of California-Davis, Davis CA

Investigators

Abstract

Ultrasensitive platforms that can be deployed in real-world situations to detect hundreds of molecules at once are central to environmental sustainability, forensic analysis, and human health. Current approaches to detect such molecules, known as volatile organic compounds (VOCs), are largely limited by technical capabilities, cost, and complexity. Optical techniques that utilize light to detect and untangle the complexity of VOC signals are promising but still under development. The platform developed in this CAREER project features novel nanomaterials that can be activated with light to selectively capture and detect airborne VOCs. This new detector has high adaptability to future portable or wearable designs and has the potential to accelerate the study of VOCs in new ways. The development of the proposed detector will lay a solid foundation for the design of new sensing platforms. This project will also provide tremendous learning opportunities for students from elementary to graduate school. Major activities include the development of community focused interactive scientific demos, production of K-12 educational boxes, development of an optical summer school for high school students, and the creation and dissemination of a wide array of accessible virtual optics resources, including interactive labs. The investigator’s long-term vision involves translating plasmonic nanomaterials to sensing applications directly in complex matrices, such as breath, biofluids, and real-world environmental sites. To realize this vision, this CAREER project seeks to develop sensitive, accurate sensors for passive detection of airborne volatile organic compounds (VOCs), including chemical warfare agents, toxic industrial chemicals, urban wildfire pollutants, and exhaled breath biomarkers. Common techniques to detect VOCs, including mass spectrometry, are bulky and difficult to integrate in portable or wearable devices for continuous monitoring. On the other hand, current portable devices to detect VOCs are largely based on electrochemical detection that greatly lack specificity, sensitivity, and ease. Multiplexed detection is rare, as specific systems need to be developed for each molecule of interest. To build an effective portable device for multiplexed VOC detection suitable for real-world deployment, two complementary technologies will be integrated: (1) a multiplexed array of metal organic frameworks (MOFs) tailored to differentially enrich target VOCs, embedded with (2) metal nanostructures that enable ultrasensitive label-free readout via the surface enhanced Raman scattering (SERS) phenomena. Multiplexed detection of VOCs will be used to build advanced data models by training on gas phase samples generated in the lab. This project will lay the groundwork towards developing a miniaturized passive SERS-MOF sensor that can be deployed in point-of-use applications like breath sensing or environmental monitoring, to be conveniently read out by inexpensive portable Raman spectrometers. This high-risk/high-reward approach is fundamentally different from competing approaches commonly employed in portable devices to monitor the concentration levels of a panel of VOCs and will accelerate their detection in real world settings with great impact on human health and safety. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.