BME Postdocs Seminar: Amanda Juraski & Wasif Khan

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Dr. Amanda Juraski: “Porous Anisotropic N,O-Carboxymethyl Chitosan/Alginate Scaffolds For Neural Tissue Applications”
Dr. Wasif Khan: “Circadian Timing and Dose of Physical Activity are Differentially Associated with Cognition and Structural Brain Aging”
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Amanda Juraski, PhD
Postdoctoral Associate, Schmidt Lab
Biomedical Engineering, University of Florida

“Porous Anisotropic N,O-Carboxymethyl Chitosan/Alginate Scaffolds For Neural Tissue Applications”

Abstract: Complex tissue lesions such as peripheral nerve injuries often result in disrupted tissue architecture, mechanical properties, and gene expression. In the case of peripheral nerve injuries, there is also limited spontaneous axonal regeneration due to the low regenerative capacity of adult neurons. To overcome these challenges, innovative strategies combining scaffolds and gene therapies that modulate inflammation offer a promising route for regeneration. Anisotropic scaffolds, which mimic the natural tissue architecture, are particularly promising for enhancing tissue differentiation and promoting nerve regeneration. Unidirectional freeze-drying is an effective, cost-efficient method for fabricating these scaffolds, enabling the production of tunable, porous structures. In this study, we explored the use of carboxymethyl chitosan (N,O-CMCS) and alginate, both biopolymers with distinct physicochemical properties, in the fabrication of anisotropic scaffolds for peripheral nerve regeneration via unidirectional freeze-drying. The scaffolds were characterized by their morphological, physicochemical, and biological properties, including their ability to support fibroblast and neuronal cell survival in vitro. The scaffolds had linearly aligned pore structure and were stable under simulated physiological conditions. Moreover, the presence of protonated amino groups on N,O-CMCS promoted optimal neuronal cell viability. To show the scaffold’s application as a gene delivery system, DNA molecules were adsorved and then released by N,O-CMCS/Alginate scaffolds, with all DNA molecules released in one hour of immersion. The results suggest that N,O-CMCS/Alginate scaffolds hold significant potential for peripheral nerve regeneration, offering insights into material interactions with cells and to the design of combinatorial therapies aimed at enhancing neural tissue engineering applications.

Bio: Dr. Amanda de Castro Juraski is a Postdoctoral Research Associate at the Schmidt Lab at the University of Florida, where she’s developing hydrogel-mediated delivery devices for exosome therapy in spinal cord injury. She earned her Ph.D. from the University of Sao Paulo, Brazil, with a dissertation focused on porous scaffolds for gene delivery and regenerative medicine in neural tissue applications. Dr. Juraski has extensive experience in biomaterials, including creating a bioink for 3D printing of neural tissue models and developing ibuprofen-loaded chitosan films for drug delivery in primary spinal cord neurons. She has given numerous presentations at conferences, is part of the LatinXinBME community, and was the founder and president of the first Student Chapter of the Brazilian Society of Biomedical Engineering. Beyond her research on neural tissue engineering, her secondary expertise lies in the exciting field of creating baked goods that her lab mates can’t stop talking about.
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Wasif Khan, PhD
Postdoctoral Associate, Fang Lab
Biomedical Engineering, University of Florida

“Circadian Timing and Dose of Physical Activity are Differentially Associated with Cognition and Structural Brain Aging”

Abstract: Physical activity is increasingly recognized as a modifiable factor for healthy brain aging. Yet, the influence of activity dose below guideline levels, as well as the timing of activity across the day, on cognition and brain aging remains unclear. In this talk, I will present findings from our analysis of 45,892 older adults in the UK Biobank with accelerometer-derived physical activity, cognitive assessments, and structural brain MRI. By examining moderate-to-vigorous physical activity (MVPA), we evaluated associations with cognitive domains and regional brain volumes. Our results reveal that higher MVPA is linked to improved performance in reasoning, memory, executive function, and processing speed, alongside structural differences in subcortical and cortical regions critical for emotion, working memory, and perceptual processing. Importantly, we identify that the timing of activity—particularly during the midday-afternoon and evening—carries distinct implications for cognitive and brain health. These insights refine the understanding of dose-response and circadian effects of activity on the aging brain and highlight the potential of circadian-informed exercise prescriptions as strategies to promote cognitive resilience in later life.

Bio: Dr. Wasif Khan is a Postdoc Associate at SMILE Lab in J. Crayton Pruitt Family Department of Biomedical Engineering at the University of Florida. Dr. Khan is working in SMILE lab at the BME and Wong lab the Norman Fixel Institute for Neurological Diseases, University of Florida. His research sits on the nexus of cognitive aging, neuroimaging, and artificial intelligence to identify modifiable lifestyle and neural factors to prevent and slow down cognitive aging and neurodegeneration. He focuses particularly on modifiable lifestyle factors, especially physical activity (PA), and their relationship to neuroimaging biomarkers and systemic health measures, which influence the risk of Alzheimer’s disease and related dementias (ADRD). By integrating large-scale population datasets with multimodal neuroimaging, Dr. Khan aims to characterize the biological and behavioral signatures of cognitive resilience and vulnerability in aging populations. This interdisciplinary approach is motivated by a strong commitment to improving brain health outcomes among individuals at elevated risk for neurodegeneration. His recent work on medical foundation model was featured in UF Health News.