MRI: Track 1 Acquisition of a High-resolution Infrared Microscope Based on the Photothermal Effect

This award is funded by the Major Research Instrumentation Program and managed by the Division of Chemistry. Professors Potma and Fishman from the University of California, Irvine (UCI), on behalf of 20 investigators in 8 different departments across the university, are acquiring an optical photothermal infrared (OPTIR) microscope system. This new type of microscope makes it possible to visualize a wide range of samples, from biological tissues to polymers to novel micro-structured materials. The images produced with the OPTIR microscope platform reveal the molecular content of the samples using contrast derived from the sample’s specific chemical bond vibrations. This unique system will support cutting-edge scientific programs at UCI, foster research collaborations with California State University Fullerton, and accelerate collaborative projects with industry partners. In addition, the requested instrument will be incorporated into several graduate courses and will play a critical role in a diversity-enhancing summer program. Microscopic imaging based on chemical bond vibrations permits the interrogation of samples without using extrinsic labels. Vibrational microscopy is an indispensable tool for the chemical analysis of micro-structured samples, from biological specimens to engineered and self-assembled soft matter systems. Commercial vibrational microscopes fill an important need, yet limitations in imaging speed, spatial resolution, and sensitivity have hampered their implementation in a wider range of imaging applications. The recently developed OPTIR microscope has overcome such limitations as it enables sensitive, background-free vibrational imaging based on mid-infrared absorption at sub-micrometer resolution. These new capabilities will be leveraged to drive advanced research programs in biological materials, including the development of mid-infrared tags, chemical mapping of skin and bioprosthetic heart valves, identification of therapeutic agents in brain tissues, and chemical analysis of cells in microfluidic devices. The system will also propel research projects in the area of soft materials, exemplified by label-free imaging of coacervates, self-assembled elastic networks, crystallin proteins of the eye lens, aerosol particles, and microdroplets. Furthermore, the OPTIR microscope will open new doors in the field of micro- and nano-structured solid-state materials, enabling projects focused on structures with infrared-active phonon polaritons, low-dimensional condensed materials, two-photon polymerized microstructures, as well as cerium oxides. 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.