Towards label-free single virus identification with nano-optomechanofluidics

University Of Illinois At Urbana-Champaign, Urbana IL

Investigators

Abstract

PI: Gaurav Bahl, Mechanical Science and Engineering University of Illinois at Urbana-Champaign CCSS-1509391 1- Proposal Title: Towards label-free single virus identification with nano-optomechanofluidics 2- Brief description of project goals: We aim to experimentally demonstrate simultaneous optical and mechanical sensing of single virus nanoparticles that can permit rapid label-free identification. 3- Abstract: 3a Nontechnical abstract Throughout history, viral diseases have inflicted great damage to human populations. Swift identification of a viral pathogen can enable a rapid healthcare response for arresting major outbreaks, and even for speedy drug development. This pressing need is highlighted by outbreaks of H1N1, H5N1, SARS, and Ebolavirus over the last decade. Simultaneous sensing of optical and mechanical properties of viruses could permit the rapid identification of individual virus particles without any chemical tests. This is a new perspective in comparison to existing optical-only or mechanical-only methods that provide limited information. This proposal addresses the associated fundamental problems of measurement throughput, sensitivity, and particle identification by means of a novel nanofluidic opto-mechanical resonator. Such devices could some day be deployed in the field for the label-free identification of viral pathogens, and for generating a swift response by healthcare authorities. In pharmacological studies, these devices could assist in drug discovery. The proposed work is fundamentally interdisciplinary and of high value from an educational perspective. This project provides rich opportunities for the training of students at all levels (graduate, undergraduate, high school) at the intersection of optical physics, solid mechanics, and fluid mechanics, using advanced experimental tools. The STEM education impact of this work will be broadened through the development and distribution of educational activities on the optical measurement of Brownian motion of microparticles. These activities will be targeted towards K-12 students at local schools, with wider distribution through existing on-campus partners. An undergraduate research assistant will also be recruited for the research and educational efforts with preference towards underrepresented groups. 3b Technical abstract Currently, fast label-free techniques for detecting viral nanoparticles rely on either photonic sensing or on vibrational mass sensing, but not both, and can only provide limited one-dimensional information. For instance, mechanical methods primarily operate on the principle of mass-loading of a resonator and the associated frequency. In this manner, the mass of a particle can be estimated with extremely high resolution, but size and density are not obtainable without additional assumptions. Photonic methods, in contrast, rely on the shift of optical resonance frequency or optical mode splitting. This provides information on the polarizability, approximate size of a nanoparticle, but does not permit further identification. As a result, there remains an ambiguity in the label-free identification of a pathogen (as opposed to mere detection) without the use of specific antibody binding or chemical processes. Having both optical and mechanical properties can shed much needed light on a single virion's size, mass density, and optical density (or polarizability), and could help narrow down the protein folding and virus structural properties. This project has multiple objectives (1) Elucidate the fundamental limits of sensing single virions with simultaneous optomechanical measurements using a nano-optomechanofluidic device. (2) Develop models of optical as well as mechanical noise sources, and incorporate the effects of radiation pressure and optomechanical back-action. (3) Develop a method of throughput enhancement in mechanical resonance sensing, by using simultaneous optical information to spatiotemporally locate the nanoparticles. (4) Improve the ability to detect and identify single virus particles, not only based on their optical properties but also their mass, through the use of nano-optomechanofluidic resonators.