An Optical Microsensor Utilizing Genetically Programmed Bioreceptor Layers for Selective Sensing

Abstract

Protein engineering is a rich technology that holds the potential to revolutionize sensors through the creation of highly selective peptides that encode unique recognition affinities. Their robust integration with sensor platforms is very challenging. The goal of this research project is to combine expertise in micro-electro-mechanical systems (MEMS) and biological/protein engineering to develop a selective sensor platform. The key enabling technology in this work is the use of biological molecules, the <italic>Tobacco mosaic virus</italic> (TMV) and its derivative, <italic>Virus-Like-Particle</italic> (VLP), as nanoreceptor layers, in conjunction with a highly sensitive microfabricated optical disk resonator. This work will present a novel method for the integration of biological molecules assembly on MEMS devices for chemical and biological sensing applications.

Particularly in this research, TMV1Cys-TNT and TMV1Cys-VLP-FLAG bioreceptor layers have been genetically engineered to bind to an ultra-low vapor pressure explosive, Trinitrotoluene (TNT), and to a widely used FLAG antibody, respectively. TNT vapor was introduce to TMV1Cys-TNT coated resonator and induced a 12 Hz resonant frequency shift, corresponding to a mass increase of 76.9 ng, a 300% larger shift compared to resonators without receptor layer coating. Subsequently, a microfabricated optical disk resonator decorated with TMV1Cys-VLP-FLAG was used to conduct enzyme-linked immunosorbent assay and label-free immunoassays on-a-chip and demonstrated a resonant wavelength shift of 5.95 nm and 0.79 nm, respectively. The significance of these developments lies in demonstrating the capability to use genetically programmable viruses and VLPs as platforms for the display and integration of receptor peptides within microsystems.

The work outlined here constitutes an interdisciplinary investigation on the integration capabilities of the bio-nanostructure materials with traditional microfabrication architectures. While previous works have focused on individual components of the system, this work addresses multi-component integration, including biological molecule surface assembly and fabrication utilizing both top-down and bottom-up approaches. Integrating biologically programmable material into traditional MEMS transducers enhances selectivity, sensitivity, and simplifies fabrication and testing methodologies. This research provides a new avenue for enhancing sensor platforms through the integration of biological species as the key to remedying challenges faced by conventional systems that utilize a wide range of polymers or metals for nonspecific bindings.