Jiaozhi (George) Lu, Ph.D.*
Division of Chemistry and Chemical Engineering
California Institute of Technology
Monday, February 11, 2019
10:00 a.m. – 11:00 a.m.
Emory University, Health Sciences Research Building (HSRB)
Georgia Tech: UAW 3115/ Georgia Tech: TEP 208
“Biomolecular Engineering of Gas-filled Protein Nanostructures For Imaging Cellular Function in Deep Tissue”
Genetically encoded fluorescent reporters such as green fluorescent protein (GFP) have revolutionized biomedical research by enabling observations of specific molecular processes in engineered cells and transgenic animals. However, such optical agents are fundamentally limited by the penetration depth of light in opaque tissues. As cell therapies and basic biology studies advance towards rodent models and ultimately humans, this limitation becomes increasingly severe. Therefore, we aim to develop new classes of genetically encoded agents that can be visualized with imaging modalities capable of reaching deeper tissues. In this talk, I will describe the engineering of gas vesicles (GVs), a class of gas-filled protein nanostructures evolved in photosynthetic microbes as the means to regulate their cellular buoyancy. GVs are hundreds of nanometers in size, enclosed by a 2-nm protein shell that is permeable to gas but excludes liquid water. The material properties of these gas-filled compartments, such as magnetic susceptibility and refractive index, are substantially different from those of the surrounding aqueous tissues, enabling the robust detection of GVs by magnetic resonance imaging (MRI) and optical coherence tomography (OCT). Uniquely, such contrast is “erasable” by ultrasound pulses at specific threshold pressures, which permits selective imaging of these agents without background tissue contrast and multiplexed imaging of different genotypes of GVs. The ability of GVs to be genetically encoded and engineered opens the possibility of using this new biomaterial in a wide range of applications, especially in synthetic biology and cellular therapeutics.
George Lu is an NIH K99 postdoctoral fellow in the laboratory of Mikhail Shapiro in the Department of Chemical Engineering at the California Institute of Technology (Caltech), where he arrived after receiving his Ph.D. in Biochemistry with Stanley Opella at the University of California, San Diego (UCSD) and completing his undergraduate studies at the University of Alberta. George’s research sits at the intersection of biomolecular engineering and structural biology, and focuses on the development of novel technologies for quantitative biological imaging and cellular control. His work on genetically encoded imaging agents was recognized by the Young Investigator of the Year 2018 award from the World Molecular Imaging Society, and was featured on the cover of Nature Materials. Personal website link: http://georgelu.org/
Host: Francisco Robles