Elucidating Bio-Nano Interface Atomic Structure and Peptide Directed Nanoparticle Formation

With the support of the Macromolecular, Supramolecular and Nanochemistry Program in the Division of Chemistry, Gregory Holland of San Diego State University is developing atomic and molecular level structural understanding of nano-bio interfaces and the influence of nanoparticle curvature, mesoporosity and morphology on biomolecular ligand structure, dynamics and organization on nanoparticle surfaces. The inorganic cores and the biomolecular ligand coatings are structurally distinct entities but strongly influence each other synergistically determining the collective properties of the nanoparticle system. The systems of interest include a range of silica nanostructures with varying morphology and naturally inspired hydroxyapatite nanomaterials functionalized with protein- and lipid-based ligands. Elucidating the atomic, molecular and nanoscale detail of biomolecular assembly on nanomaterials, developing novel peptide-directed nanoparticle syntheses and understanding the surface chemistry of biomolecules on nanoparticles is the research focus. This fundamental chemical knowledge could contribute to the development of next generation devices and sensors that couple nanomaterials with biomolecular functionality. The project is creating valuable research training opportunities for students at various levels that is further integrated with outreach activity development. Dr. Holland is building a highly interdisciplinary research and education program on nanoparticle surface characterization. The vast majority of chemically synthesized and naturally occurring nanostructures, regardless of their chemical compositions, inorganic core, morphology and crystallinity, are coated with a ligand shell. The primary goal of this research is to determine the atomic and molecular level structure of nano-bio interfaces and to exploit biomolecules, including peptides and lipids as ligands in nanoparticle synthetic strategies. There are two main foci: (1) to investigate biomolecules assembled on a range of nanostructured silicas including colloidal monodisperse spheres, highly defective, branched fumed silica, and mesoporous silica nanoparticles where the behavior of biomolecules encapsulated within nanopores is the focus; and (2) naturally inspired hydroxyapatite nanorods and nanosheets synthesized with peptides as the templating agents. A combination of physical/analytical techniques will be used in the research, including solid-state NMR spectroscopy, electron microscopy and molecular dynamics simulation (MDS) to determine the structure and assembly of peptides and lipids at the interface of these systems and elucidate the influence of nanoparticle curvature and morphology on ligand architecture. This work is expanding on the synthetic and characterization methods available to the global nanoscience community for improved fundamental understanding of nano-biostructures. 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.