Date of Award

7-8-2020

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Applied Science

First Advisor

Anindya Ghosh

Abstract

Hydrogels have existed for more than half a century, and today they have many applications including tissue engineering. We have synthesized hydrogel scaffolds based on low cost and biodegradable polymer like hydroxypropyl guar (HPG) and applying them for bone tissue engineering. We have fabricated hydrogel matrices without any toxic chemical crosslinker to avoid possible toxicity in fabrication. We followed two methods of fabrication for HPG based hydrogels. One is via physical crosslinking, by simply mixing poly(vinyl alcohol) (PVA) with HPG and the other one is grafting poly(vinyl caprolactam) (PNVCL) on HPG via radical polymerization. For the first method, we developed the PVA/HPG hydrogel using a simple freeze-thaw cycle. The material was characterized using different analytical techniques such as SEM, EDX, FT-IR, etc In vitro biomineralization studies of hydrogel matrices also were performed by immersing scaffold in stimulated body fluid for 7 and 14 days. The results obtained from the SEM revealed that the HPG/PVA hydrogel has porous morphology, which is suitable for bone tissue regeneration. Moreover, the scaffold could mineralize and form apatite like structure. Multiple cell assays such as MTT(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide), Trypan blue, EB/AO (Acridine orange/ethidium bromide) and alkaline phosphatase were used to determine cell viability and functional activities of the cells. As revealed by the assays, both HPG/PVA and HPG/PVA/n-HA promoted cell growth and differentiation and acted as better scaffolds compared to PVA alone. The graft copolymer HPG-g-PNVCL were also synthesized and it was characterized using NMR, FT/IR, and TGA. Furthermore, various reaction conditions such as time, temperature, initiator, and monomer concentrations for the graft copolymerization have been optimized. Using UV/vis spectroscopy, the lower critical solution temperature (LCST) for HPG-g-PNVCL was observed at 34 °C, which is close to the rheological gel point of 33.5 °C. We have checked the utility of HPG-g-PNVCL hydrogel as a scaffold for bone cell growth, and studies showed that osteoblastic MC3T3 cells can grow rapidly for various time periods. In vitro drug release studies of the injectable hydrogel were also studied using ciprofloxacin as a model drug.

Download

Included in

Chemistry Commons

Share

COinS