College of Engineering

BMEBT Seminar & PHD Defense by Manisha Jassal

Date(s): 11/20/2012 10:00 AM - 11/20/201211:00 AM
Location: Textiles Conference Room - 101E
Contact: Dr. Sankha Bhowmick 508-999-8619

TOPIC: "Use of sub-micron sized electrospun fibers to enhance the surface functionality and their subsequent characterization”

ABSTRACT: Tissue regeneration relies on building carefully crafted scaffold material in the micron-submicron scale and imparting specific functionality to them in order to best mimic the in vivo environment in terms of chemical composition, morphology, and surface functional groups. Fibrous meshes with structural features at the micron-submicron level for ideal 3D tissue regeneration scaffolds can be an inexpensive scale up option. Bio-inert polymers lack the functional motifs for specific bioactivity; however, functionalization of the scaffolds can provide biological functions to actively induce tissue regeneration and promote cell adhesion by targeting specific cell-matrix interactions. It has already been established that sub-micron sized fibers are better than the micron-sized fibers as fibroblast cells attach preferentially to these sub-micron sized fibrous scaffolds. The surface functionality of polymer surfaces can be enhanced even more through various functionalization techniques such as hydrolysis, aminolysis and RGD (arginine-glycine-aspartic acid) peptide coupling that result in better cell attachment. It is therefore important to characterize the scaffolds and understand the relationship between the efficacy of the functionalization, the surface properties of the scaffolds, and their performance. Poly(ε-caprolactone) (PCL) is a biodegradable, aliphatic polyester that has found applications in various fields such as drug delivery systems, medical devices, tissue engineering and more. Both aminolysis and hydrolysis can be considered controlled degradation reactions for PCL and it has been reported that degradation behavior of nano-scale material would be different from macro-scale materials. The mechanism of PCL hydrolysis is well understood on bulk polymer materials. But the exact mechanism behind hydrolysis of electrospun fibers is not very clear and requires detailed investigation. After elucidating the exact mechanism of functionalization, the next step would be to correlate the efficacy of functionalization to the cellular response. From the literature, we can conclude that functionalization does alter the cellular behavior; however, a systematic study of functional group quantity variation on cellular response, at least for fibrous scaffolds, is required. Similarly, polymer functionalization also finds applications in environmental engineering in form of ion-exchange fibers. In addition to environmental applications, ion-exchange fibers have found their use in medical/pharmaceutical applications for transdermal drug delivery. It is my understanding that the sub-micron sized fibers are better for ion-exchange applications based on specific surface area ratio and my goal would be to establish the role of polymer form on the ion-exchange capacity. Also, ion-exchange kinetics for resins/membranes is well established and documented, but the ion-exchange fiber kinetics is poorly understood. Extending our current knowledge to formulation of a kinetics model for ion-exchange fibers would lead to a better understanding of the process.

Through my research, I hope to gain a basic understanding of the functionalization process mechanism and the reaction kinetics for sub-micron sized electrospun fibers. This would help us to establish a control over the functionalization process and identify the optimum conditions for specific end use applications that include tissue engineering scaffolds and ion-exchange fibers for drug delivery.

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