Halim Ayan, Ph.D.
Associate Professor, Department of Bioengineering; Department of Mechanical, Industrial & Manufacturing Engineering,
The University of Toledo
halim.ayan@utoledo.edu
Biography:
Halim Ayan received the B.Sc. (summa cum laude) degree in mechanical engineering from Ege University, Izmir, Turkey, in 2001, and the Ph.D. degree in mechanical engineering and mechanics from Drexel University, Philadelphia, PA, USA, in 2009. His doctoral study was on development and characterization of a novel non‐thermal atmospheric pressure dielectric barrier discharge plasma with nanosecond rise time high voltage pulses for medical and biological applications.
From 2009 to 2012, Dr. Ayan was an Assistant Professor with the Department of Engineering and Physics, Murray State University, Murray, KY, USA and Department of Mechanical Engineering, University of Kentucky, Paducah, KY USA. He has been an Assistant Professor from 2012 to 2018, and since 2018 an Associate Professor with the Department of Bioengineering and the Department of Mechanical, Industrial and Manufacturing Engineering, University of Toledo, Toledo, OH, USA, where he has been teaching both bioengineering and mechanical engineering courses.
Dr. Ayan’s current research interests include electric plasmas, applications of non-thermal plasmas for sterilization of planktonic bacteria and biofilms, treatment of cancer cells, biopolymer surface modification to enhance cellular functions for tissue engineering applications. He has received 1 NSF and 2 USAF-MDA research grants; published 1 book, 2 book chapters, 17 peer-reviewed journal articles, and 1 patent; and delivered several podium presentations at international conferences. Dr. Ayan serves as a reviewer for several internationally recognized journals and is a founding member of the International Society of Plasma Medicine and the International Society for Biofabrication.
Topic title: Mechanically Primed Stem Cell Guided Annulus Fibrosus Regeneration
Abstract:Recurrence of intervertebral disc (IVD) herniation is the most important factor leading to chronic low back pain. There is a need for an effective annulus fibrosus (AF) repair strategy that can deliver cells and biologics to IVD injury site to limit the progression of disc degeneration and promote disc self-regeneration. In this study, a mechanically-conditioned scaffold encapsulated with human adipose-derived stem cells (ASCs) was investigated as a potential treatment strategy for AF defects. Equiaxial strains and frequencies were applied to ASCs-encapsulated scaffolds to identify the optimal loading modality to induce AF differentiation. Equiaxial loading resulted in 2–4 folds increase in secretion of extracellular matrix proteins and the reorganization of the matrix fibers and elongations of the cells along the load direction. Further, the equiaxial load induced region-specific differentiation of ASCs within the inner and outer regions of the biphasic scaffolds. Gene expression of AF markers was upregulated with 5–30 folds within the equiaxially loaded biphasic scaffolds compared to unstrained samples. The results suggest that there is a specific value of equiaxial strain favorable to differentiate ASCs towards AF lineage and that ASCs-embedded biphasic scaffold can potentially be utilized to repair the AF defects.
