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Pirkey Lectureship Seminar – “Mesoporous silica nanoparticle supported lipid bilayers (protocells) for individual cell targeting and CRISPR delivery” by Jeff Brinker
February 21 @ 3:30 pm - 4:30 pm
Host: Dr. John Ekerdt
Mesoporous silica nanoparticle-supported lipid bilayers (protocells) are an emerging class of nanocarriers that synergistically combine the advantages of mesoporous silica nanoparticles (MSNs), including tunable size, shape, and pore characteristics that facilitate high loading capacities, with the advantages of liposomes such as enhanced circulation, ease of synthesis, biocompatibility, flexible formulations, and capacity for targeting. Protocell assembly occurs upon fusion of the liposome to the surface of the MSN, resulting in encapsulation of the MSN core within a conformal supported lipid bilayer (SLB). Further conjugation of the SLB with polymers, such as PEG, or targeting ligands confer stability and enable specific binding and internalization. We have demonstrated this platform to be a plug-and-play nanocarrier, capable of housing disparate cargos ranging from small molecule drugs for cancer therapeutics to large biomolecules including large DNA constructs such as plasmids for use in gene therapy and applying recently developed CRISPR-Cas9 technology for precise gene editing and modulation. Furthermore, the flexibility of the system extends to the targeting potential viz surface chemistries that accommodate antibodies, affibodies, and other molecules to enhance cell-specific delivery. Zwitterionic protocells conjugated with an anti-EGFR antibody and loaded with the cytotoxic drug gemcitabine preferentially bound to and killed individual EGFR-positive REH leukemia cells ex ovo and avoided their EGFR-negative counterparts while maintaining properties that are generally viewed as necessary for successful therapeutic efficacy. These properties include size monodispersity, high colloidal stability over time, minimal nonspecific binding or uptake by the mononuclear phagocytic system, high capacity for and precise release of therapeutic cargos, and low cytotoxicity. Furthermore, cationic protocell formulations can package and deliver large plasmid constructs that encode for CRISPR-Cas9 components. In a HER- 2 expressing cell line, protocells modified with an anti-HER-2 affibody successfully targeted and delivered plasmids resulting in GFP and RFP expression, demonstrating successful CRISPR delivery. Unmodified protocells were used for transfection of Cas9-mediated activation of TP53 via the Synergistic Activation Mechanism (SAM), resulting in increased p53 production. Overall we have demonstrated the potential of the protocell as a platform nanocarrier capable of targeting a range of cell-surface markers and delivering diverse cargos while maintaining advantageous properties that will be necessary for viable in vivo use.
Paul Durfee2, Ayse Muniz3, Yu-Shen Lin2, Achraf Noureddine2, Darryl Sasaki1, Oscar Negrete1, Kim Butler1, C. Jeffrey Brinker1, 2
- Sandia National Labs, Albuquerque, NM, United States.
- Chemical and Biological Engineering and Center for Micro-Engineered Materials, University of New Mexico, Albuquerque, NM, United States.
- BioInterfaces Institute, University of Michigan, Ann Arbor, MI, United States.
Brinker received his B.S., M.S., and Ph.D. degrees in ceramic science and engineering at Rutgers University. He joined Sandia National Laboratories in 1979 where he is currently one of four Sandia National Laboratory Fellows (the highest technical position at Sandia). He is jointly employed by the University of New Mexico, where he is Distinguished and Regent’s Professor of Chemical and Biological Engineering with joint appointments in the departments of Chemistry, Molecular Genetics and Microbiology, and the Cancer Center. Over his thirty seven year career at Sandia and UNM, Brinker has made numerous pioneering contributions to processing, characterization, and understanding of porous and composite nanostructured materials and to the development of novel functional bio/nano interfaces and nanoparticle drug delivery platforms. Brinker has received some of the highest honors in the materials research field including the Department of Energy Ernest O. Lawrence Memorial Award in Materials Science and the Materials Research Society MRS Medal along with five R&D100 Awards. In 2002 he was elected to the National Academy of Engineering. He is Fellow of the American Ceramic Society and Materials Research Society and in 2015 was elected into the National Academy of Inventors.