Biomolecular Sciences Student Research Presentations

Stephanie Rood, Ph.D. Student

Cold Atmospheric-Pressure Plasma: A Novel Approach of Microbial Inactivation on Crop Seeds
 

In the U.S. agricultural industry alone, annual losses are estimated to reach a staggering $21 billion due to plant pathogens such as Pseudomonas syringae and Fusarium graminearum. Additionally in the U.S., foodborne pathogens like E. coli O157:H7 and Salmonella enterica are responsible for approximately 48 million illnesses and 3,000 deaths each year. Both plant pathogens and foodborne illnesses display a clear risk to the viability of seeds and a safety risk for their subsequent sprouts consumed directly by humans. Our research investigates the use of cold atmospheric-pressure plasma (CAP) generation of reactive oxygen and nitrogen species (RONS) as a novel method for pathogen inactivation on crop seeds, focusing on both plant and foodborne pathogens. These results demonstrate that CAP treatment can reduce pathogen populations by up to 99.9% on a variety of crop seeds (sweet corn, popcorn, cucumber, mung bean, and radish). Reductions of approximately 3-log CFU were seen across Pseudomonas syringae and Fusarium graminearum as well as E. coli O157:H7 and Salmonella enterica upon 15-minute treatments of CAP. Germination assays display that CAP treatment does not adversely affect the germination rate or seedling vigor between treated and untreated seeds. Our findings suggest that CAP offers a novel and environmentally friendly alternative to traditional harsh chemical treatments allowing for a potential reduction of crop loss and improvement of food safety.
 

Committee:
Dr. Ken Cornell, Department of Chemistry and Biochemistry
Dr. Daniel Fologea, Department of Physics
Dr. Javier Ochoa-Reparaz, Department of Biological Sciences

Stephanie Tuft, Ph.D. Candidate

Structure-Property-Processing Relationship in Demineralized Allogeneic Cancellous Bone Bioscaffold Material
 

Demineralized bone matrix (DBM) is a critical material in orthopedic and reconstructive surgery, widely employed to promote bone regeneration in procedures like spine fusion, craniomaxillofacial repair, and hip arthroplasty. DBM functions both as a structural scaffold for new tissue growth and as a source of biochemical signals, including growth factors and extracellular matrix (ECM) molecules, that direct cells along an osteogenic pathway. Allogeneic cancellous bone grafts have demonstrated superior outcomes compared to bone morphogenetic protein combined with autograft, yet a complete understanding of their protein composition, micro-structure, cellular response, and gene expression changes remains incomplete.

This study analyzed two types of freeze-dried human cancellous bone allogeneic scaffolds (Samples A and B), each prepared using a distinct decellularizing protocol designed to retain critical ECM molecules, such as structural collagens and osteogenic proteins. We performed proteomic profiling, micro-structure analyses, and evaluated subsequent cell response and gene expression to determine if these manufacturing differences yield scaffolds with varying functional impacts on cell growth and differentiation. We hypothesized that greater availability of osteogenic proteins and surface area would enhance both osteogenic differentiation and cell proliferation.

Our findings reveal that the processing method profoundly affects the resulting scaffold properties. Sample A exhibited increased surface area, roughness, and elastic modulus, which correlated with greater cell adhesion and proliferation, yet surprisingly resulted in less osteogenic differentiation. Conversely, Sample B supported cell adhesion and proliferation while potentially promoting more osteogenic differentiation. These results demonstrate that the unique processing methods exert a substantial influence on the structure, composition, and biological properties of the bioscaffold, which may ultimately dictate the regenerative success of allogeneic cancellous bone graft materials.

Committee:
Dr. Julia Oxford, Department of Biological Sciences
Dr. Ken Cornell, Department of Chemistry and Biochemistry
Dr. Daniel Fologea, Department of Physics