Development of High-performing Nanoplasmonic Biosensors with Novel Thin Films and Metasurfaces

With the support of the Chemical Measurement and Imaging (CMI) Program in the Division of Chemistry, Professor Quan Cheng and his group at the University of California-Riverside are working to develop new optical biosensors to improve molecular sensing of proteins and small molecules via methods that do not require chemical changes to the targets being sensed. These new approaches are based on use of metals structured in a way at the nanometer scale so that light of a given energy generates waves of electrons on the surface of the metals, with the energy being impacted by the presence of molecules near the surface of the sensor.

These nanoplasmonic sensors are anticipated to offer new avenues for detection of small molecules that could not be achieved previously, potentially leading to significantly improved detection of biological molecules in the longer term. Such sensing methods are needed for a wide range of applications, including for medical diagnostics, for food/water safety monitoring, and for drug discovery.

The Cheng group will focus their research efforts on generating plasmonic substrates with aluminum instead of traditional metals such as gold or silver. This approach has a number of potential advantages, including better performance, lower cost, high sustainability, and long-term environmental benefit. The highly interdisciplinary nature of the project offers opportunities for students to gain broad experience in surface chemistry, materials science, biology, and bioanalytical chemistry.

In this work, Professor Cheng and his group are working with emerging plasmonic materials in thin film and nanostructured, meta-surface formats. Methodologies are designed to achieve high detection sensitivity with aluminum films in the Kretschmann configuration and build new surface chemistry allowing convenient functionalization of the interface. The core technical innovation of this project is in developing aluminum plasmonic applications, with the intrinsic plasmonic properties leveraged into improvements in the capacity of several analytical techniques including surface plasmon resonance (SPR), SPR imaging (SPRi), and terahertz (THz) sensing.

New strategies will be developed to eliminate technical barriers that have limited application of aluminum, and THz sensing with aluminum metasurfaces will be demonstrated for the characterization of inter- and intra-molecular, weak bonding networks. Finally, a novel biosensor with indium plasmonic arrays and SPR imaging is being developed. The exploration of indium thin films could offer new substrates for label-free detection and provide a tactic to mitigate against limitations associated with oxide coatings.

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.