The objective of this Major Research Instrumentation (MRI) award is to develop a versatile, multifunctional coherent anti-Stokes Raman spectroscopy (CARS) imaging system that will be capable of nondestructive and noninvasive measurement for nanoscience, biology, and medical research with 3D confocality and nanoscale resolutions. The project will integrate morphology characterization, microscale CARS-based multimodal nonlinear optical imaging and tip-enhanced CARS imaging capabilities in a single system. Deliverables include a multi-functional CARS system, documentation of research results, and engineering student education.
If successful, the results of this project will create a key equipment in a core facility that serves as a cross-disciplinary and multi-organization research and education platform in the region. The instrument will support education for graduate and undergraduate students for a diverse group of people, including women and underrepresented minority students. The successful development of this instrument will open many research opportunities in nanoscience/technology, material science, cellular biology and other fields in the United States. Graduate and undergraduate students will benefit through involvement in the research and classroom instruction. The engagement of K-12 students and teachers in this project will also establish new partnerships between the University and K-12 schools.
The ability to simultaneously observe and characterize morphological, structural, and functional properties of materials and organisms at mirco- and nano-scales has been an important catalyst for many major discoveries in materials science, cellular biology, and other fields in last decades. The traditional chemical labeling widely used in optical microscopy could provide such ability, but unfortunately it may alter cells and materials, thus impeding determination of their true structure, function and response. The solution is to develop label-free techniques, for example coherent anti-Stokes Raman (CARS) microscopy. CARS can be used to track processes and provide functional readouts of differentiation based on different molecule vibrations in the sample. It circumvents the need for extrinsic labels, allowing real-time observation of dynamic phenomena in samples and also enables noninvasive detection even in the presence of fluorescence background. The project supported by this award was to develop a versatile, multifunctional CARS imaging system that will be capable of nondestructive and noninvasive measurement of correlated geometrical, chemical, and biomedical properties such as shape, dimension, and molecule bonding with 3D imaging and nanoscale resolutions. We successfully designed and developed multifunctional CARS imaging system. There are many applications in chemical and biological fields. A comparison study of microalgae cells using spontaneous Raman and CARS spectroscopy and microscopy was conducted in the project period. Based on the CH group vibrational stretching mode in lipid, CARS microscopy is able to visualize the abundant lipid drops in microalgae cells and as an ideal tool to study the biofuel generation from microalgae. The chemical information in the CH-stretch regions of Raman and CARS spectra could also give important information for early detection of some diseases, for example peripheral arterial disease (PAD), which presents in at least 25% of individuals over the age of 70 years. In our experiments, Raman and CARS spectroscopy in CH-stretch region has been applied in the study for the rapid and effective analysis for PAD. Both spontaneous Raman and CARS in conjunction with PC-DFA method were applied. The overall accuracy for Raman and CARS was 86.3% and 80.3%, respectively. Considering the biomedical variation, both overall accuracies are acceptable. Thus, CARS spectroscopy in CH-stretch region has been proved to be a potential tool for the rapid and effective analysis for PAD or other diseases. During the project period, we has established collaborations with Newport Technology and Applications Center in CARS spectroscopy. In addition, because the CARS imaging system delivers many capabilities, it is becoming a premiere focal point for interdisciplinary research involving scientists from many departments at UNL and UNMC. The knowledge obtained from this research project was also integrated into a graduate course of "Introduction of Nanotechnology". Multi-photon concept closely related to this project is covered.