The PIs propose to acquire a high resolution (HR) field-emission scanning electron microscope (FESEM)to foster ground-breaking advances in ongoing specific and interdisciplinary research initiatives. The proposed FESEM will enable UM investigators with diverse scientific specialties to develop high-impact research projects not currently achievable at UM and its regional partner institutions. Materials science projects will yield novel and diverse materials and devices with potential practical applications, including microwave devices using novel ferrite-based magnetoelectric nanocomposites, flexible metal-polymer based strain gauges, improved chitosan scaffolds for tissue engineering, stable hydrogels with controlled pore structure for drug delivery, nanocapsule-based optical sensing devices with extended life time and ultra-short response time, and hybrid nanomaterials with dual magnetic/optical properties for biomolecular sensing. In cell biology, the FESEM will produce fundamental understanding of the role of cytoskeletal linkers in structuring the cytoplasmic space. In geology, investigations of nanoscale metal binding on fine-grained soils and sediments will be possible as will archaeometric and taphonomic studies aimed at identifying the origin(s) of archaeological samples and fossil deposits.
The project proposed the acquisition of a high-resolution field-emission scanning electron microscope (FESEM), the Nova NanoSEM 650, to foster ground-breaking advances in ongoing specific and interdisciplinary research initiatives at the University of Memphis (UM) in the broad areas of materials science, cell biology and geosciences. Overall, we met the proposed timeline on this 15 months project. Specifically, bidding, purchase, space renovation, instrument delivery and installation were completed in the first seven months of the award and the FESEM was operational at the UM Integrated Microscopy Center (IMC) by May 2014. During May 2014, IMC staff was trained to operate the instrument by technical personnel from the company manufacturing the FESEM. During June 2014, the PI and co-PIs as well as other interested users were trained to operate the FESEM by IMC staff. From that time on, the PI, co-PIs and interested users began working in earnest on the scientific projects described in the proposal and also to train students to operate and use the FESEM for research projects. Use of the FESEM by investigators at UM led to several scientific outcomes, including: (1) etching optical grating into tantalium oxide based waveguides to test the response characteristics of biosensors for electrochemical measurements of diverse metabolites (Dr. Lindner, Bioengineering); (2) assessing the surface morphology and composition of galvanostatically deposited layers for biosensors in order to improve on the design and performance of these sensors (Dr. Lindner, Bioengineering); (3) characterizing the nanofiber structure of chitosan biomaterials conducive to nutrient and cell signaling exchange between bone and soft tissue compartments during bone regeneration (Dr. Bumgartner, Bioengineering); (4) demonstrating the efficacy of the chitosan materials for guided bone regeneration strategies in a model appropriate for dental/craniofacial implant applications (Dr. Bumgartner, Bioengineering); (5) characterizing the surface morphology of calcium phosphate hollow spheres decorated with fine silver dots of 2-5 nm size, a novel material which demonstrated efficacy against three bacterial species causing mouth infection (Dr. Mishra, Physics), (6) analyzing polished thin sections of clay-altered impact spherules containing evidence of the terminal Cretaceous meteoritic impact event (K-P event) commonly thought to be responsible for the demise of dinosaurs and showing that spherules from Missouri and Alabama was replaced by clay minerals with radiating and pore-lining geometry with nearly identical chemical composition (Dr. Larsen, Earth Sciences; see attached images); (7) to demonstrating that the elemental analysis probe attached to the FESEM is also invaluable to identify the geographic origin of microcrystalline silica (also called Chert) used for tool crafting by Native American’s throughout southeastern North America during the past thousands of years (Dr. Larsen, Earth Sciences); (8) demonstrating that the chemical polyethylenimine (PEI) which is used for introducing genes into cells has dramatic effects on the cell shape and on the integrity of the plasma membrane, results that shed light on the mechanism of action of this chemical potentially applicable for gene therapy (Dr. Skalli, Biological Sciences; see attached image); (9) developing methods for correlative microscopy by which the overall distribution of a specific protein in a particular cell can be visualized first at the light microscopy level and then further characterized at high resolution in the same cell by FESEM (Dr. Skalli, Biological Sciences). Several key outcomes or products have also resulted from this project, including the filing of 2 invention disclosures, the award of 3 grants, the submission of 4 proposals, the publication of 6 manuscripts, the publication and presentation of 3 abstracts and 3 invited meeting presentations. Regarding broader teaching outcomes, several students have been trained to use the FESEM. From the group of Dr. Bumgartner, this includes 3 graduate students who have attended professional meetings and given presentations on their FESEM results and a dental student from the University of Tennessee who used the FE-SEM to evaluate electrospun membranes. Three additional graduate students working with Dr. Mishra (Physics) have operated the FESEM to investigate the structural features of graphene- and calcium phosphate-based materials. A post-doctoral fellow working with Dr. Lindner used the FESEM to investigate the structural features of porous nanocapsules. Regarding K12 education, 2 high school students from the summer 2014 College Research Experience for Students from High School were initiated to the operation of the FESEM for their summer research project. Dr. Skalli also lectured on the operating principle of FESEM and demonstrated its operation as part of his graduate course on microscopy. Altogether this project made a tremendous impact on the research infrastructure at UM by filling a gap in the instrumentation available to UM investigators. This enabled diverse, productive scientific projects and exposed students to state of the art FESEM technology. The research and teaching impact of this project will steadily increase in coming years as more students and post-doc are being trained in operating the FESEM and using it to obtain data for their research.
