Date of Graduation
12-2021
Document Type
Dissertation
Degree Name
Doctor of Philosophy in Chemistry (PhD)
Degree Level
Graduate
Department
Chemistry & Biochemistry
Advisor/Mentor
Chen, Jingyi
Committee Member
Wang, Yong
Second Committee Member
Heyes, Colin D.
Third Committee Member
Quinn, Kyle P.
Fourth Committee Member
Koeppe, Roger E. II
Fifth Committee Member
Thallapuranam, Suresh
Keywords
Antimicrobial application; Controlled release of FGFs; Injectable hydrogels; Silver nanoparticles; Silver/gold alloy nanostructures; Wound healing
Abstract
This work focuses on the synthesis of biocompatible polyethylene glycol (PEG)-based hydrogels, silver nanoparticles (AgNPs), and silver-gold nanocages (Ag-AuNCs) for biomedical applications. The dissertation includes two parts with Part I on the work of PEG-based hydrogel for wound healing applications and Part II on the work of Ag/Au nanostructures for antimicrobial applications. Part I studies PEG-based hydrogel for the delivery of fibroblast growth factors (FGFs) for wound healing applications, aiming to overcome the challenge of designing hydrogels capable of the sustained release of bioactive FGFs. This research develops new biocompatible anionic injectable hydrogel formulations based on Poly (Oligo Ethylene Glycol Monoacrylate-Acrylic Acid- N-Isopropylacrylamide) (POEGA-AA-NIPAM) using a simple and robust free-radical polymerization reaction. Chemical and physical properties of these hydrogels were characterized while feasibility for controlled release of FGFs from these hydrogels was examined in vitro. P(OEGA-AA-NIPAM) hydrogels were able to achieve sustained release of active human acidic FGF (hFGF1) which improved wound healing in vivo. This study promises a delivery system with tunable charge distribution for the delivery of active positively charged proteins for wound healing applications. Part II explores the effects of surface chemistry, morphology, and composition of Ag/Au nanostructures on their antimicrobial properties. It was found that the positively charged AgNPs caused a reorganization of histone-like nucleoid structuring (H-NS) protein of E. coli, resulting in enhanced antimicrobial activity while polydopamine (PDA) coating could synergize with AgNPs to increase antimicrobial killing against E. coli. The synergistic effect of PDA on antimicrobial activity of AgNPs that spectroscopic studies revealed to be from coordination of catechol group of PDA and Ag in the coating to generate reactive oxygen species (ROS). Further, Ag-AuNCs with different Ag/Aumolar ratios showed higher antimicrobial activity than pure AgNPs unveiling a synergistic effect between Au and AgNPs that depends on the Ag/Au composition and morphology of the alloy. This study provides insights on tailoring the antimicrobial properties of Ag/Au nanostructures through nanochemistry.
Citation
Niyonshuti, I. I. (2021). Synthesis of Polyethylene Glycol-Based Hydrogels and Silver/Gold Nanostructures for Biomedical Applications. Graduate Theses and Dissertations Retrieved from https://scholarworks.uark.edu/etd/4285
Included in
Nanoscience and Nanotechnology Commons, Polymer and Organic Materials Commons, Polymer Chemistry Commons