Bioanalytical and Interfacial Chemistry, Nanoscience
Our research program is applying chemically tailored interfaces, nanomaterials and nanofabrication methods to Analytical Chemistry problems.
We operate within the Department of Chemistry and the National Institute for Nanotechnology (NINT). Our projects include surface bioassay development, nanoparticle enhanced spectroscopy, molecular electronics, electrochemical surface modification, characterization and applications of green nanomaterials and instrumental development.
A powerful way to detect and quantitate biological molecules is through a biorecognition interaction. Our surface bioassay work involves the fabrication of array chips for bioanalysis via biorecognition. We are designing sensor chips for the detection and quantitation of whole bacteria, RNA and proteins. The work involves developing interfacial chemistry to effectively immobilize capture agents to the surface and to control non-specific binding for working in complex sample matrices (e.g., blood plasma). Our assay design is targeted for two specific detection platforms. One is surface plasmon resonance (SPR) imaging, a label-free method for detecting interactions at metal surfaces.
The second detection platform exploits the ability of metal nanoparticles (NPs) to enhance spectroscopic signals for bioassay detection. We are developing methods to modify the surface metal NPs of various shape and size with a mixed layer of small aromatic molecules and antibodies. The figure below left is a transmission electron microscopy (TEM) image of a gold nanorod modified with a layer of antibodies (shown as the halo around the particle). The metal NPs provide a substrate for surface enhanced Raman spectroscopy (SERS). These NP reagents are designed to recognize a captured analyte via antibody binding and the surface enhanced Raman spectrum of the small molecule is used for detection.
Other projects involve “green” nanomaterials and materials of interest in oil sands production. The need for products made from renewable resources that are biodegradable is driving a project focused on the characterization and applications of nanocrystalline cellulose (NCC). This material is derived from a variety of plant sources and has potential applications in composites. Our work is focused on nanoscale and spectroscopic characterization of NCCS a well as their application. The figure on the right is an atomic force microscopy (AFM) image of a NCC film that we are targeting for size-selective filtering and biosensing.
Asphaltenes are a significant quandary for extraction of oil sands due to their adsorption on mineral and catalyst surfaces. Understanding the physical properties of asphaltenes on surfaces is crucial for the proper and cost-effective extraction and separation of bitumen from the oil sands. We are isolating and characterizing aggregates of asphaltenes, and comparing these materials to the surface deposits that form in the presence of diluted bitumen. The emphasis id the characterization of the behavior of asphaltenes attached to surfaces using AFM.