Multiplexed spectral imaging has led to many valuable discoveries in biological studies. To further improve our knowledge of biological systems and enhance our understanding of signaling pathways, more and more proteins and other molecules are being studied simultaneously. Such studies are complex, often requiring the spectral multiplexing of optical labels. Similarly, high-throughput and/or high-data rate measurements are also needed. Our objective is to develop metal nanoparticles for highly multiplexed imaging. The goals for this project are to synthesize nanoparticles, functionalize nanoparticles, and characterize and optimize the nanoparticle performance. Work toward meeting each of these goals will be performed in parallel because frequent iteration of methods involved for each goal will be required to reach the desired final result. The development effort can serve user communities involved in a range of biological studies, including cellular labeling, particle tracking studies, protein-protein interactions, and cellular protein dynamics. This work will have broad scientific impacts, as well as social and educational and training impacts. The one-year project will integrate research and education through the training of one postdoctoral fellow and one undergraduate summer student. Although the student will be supported by this grant, he or she will participate in the NSF-supported Research Experiences for Undergraduates program, which SRI's Molecular Physics Laboratory has conducted for the past 17 years. The transformative capabilities of the enhanced imaging method will lead to greater understanding of biology, cell biology and disease processes.
Optical imaging is one of the key methods used today to improve our understanding of basic biology. A common example of such imaging is the examination of cells under a microscope in basic research to understand their function and what goes wrong when disease occurs. This knowledge can, in turn, be used to determine what might be done to treat or prevent disease. Imaging techniques may also be used to detect disease in patients. This project has developed methods to improve the amount of information that can be obtained from microscopic optical imaging. For example, different molecules such as proteins or strands of DNA or RNA may be labeled with different colors to determine how much of each molecule is present in each region of the cell. This project is directed at developing methods for expanding the number of different molecules that can be simultaneously imaged by increasing the number of colors that may be used. In particular, we are using extremely small particles of metal (metal nanoparticles) that have different colors. These nanoparticles are only a few nanometers in size, or roughly 1,000 times smaller than the diameter of a human hair. Work with particles of this size is one form of nanotechnology. In this phase of the project, we have been developing methods to produce more colors of nanoparticles than has been previously possible. Extrapolating from the current results, we may be able to provide 10 or more different colors. When more information is obtained, more powerful microscopic imaging allows better detection of disease, and this may allow earlier diagnosis, treatment, and prevention of some disease-related processes. This project has contributed to research and teaching skills through the participation of an undergraduate student and a postdoctoral fellow. The undergraduate student assisted with preparation of instrumentation for measuring the optical properties of the nanoparticles. The postdoctoral fellow worked on preparation of the nanoparticles, nanoparticle measurements, and analysis of the results.
