Dissertation/Thesis Abstract

Biocompatible Hybrid Molecular Brushes Composed of Chitosan, Polylactide, and Poly(N-vinyl pyrrolidone) as Scaffolds for Skin Wound Healing
by Chawathe, Manasi, Ph.D., University of the Sciences in Philadelphia, 2018, 160; 10904830
Abstract (Summary)

It is essential that biomaterials applied for tissue engineering support cellular growth and function. Hence, new materials are being investigated for their potential in this regard. Hybrid molecular brushes (HMB) are macromolecular constructs made up of a backbone and two or more side chain polymers of opposing natures. HMB’s tunable characteristics make it an appealing candidate as a tissue engineering substrate. We designed a two-step process of synthesis of a novel HMB with chitosan (CHI) backbone and polylactide (PLA) and poly(N-vinyl pyrrolidone) side chains. In the first step, PLA was grafted by interfacial ring opening polymerization of lactide to give chitosan-graft-polylactide (CHI-g-PLA). Next, PNVP was grafted from the CHI- g-PLA via radical polymerization of N-vinyl pyrrolidone to give chitosan- graft-polylactide-graft-poly(N-vinyl pyrrolidone) or HMB. Both the CHI-g-PLA and HMB were extensively characterized for their chemical structure and morphology. HMB, tethered to a surface, was switched between PLA and PNVP by exposing it to anisole and water respectively. Contact angles and atomic force microscopy (AFM) were used to confirm surface switching. HDF, the primary cells involved in regeneration of dermal extracellular matrix after an injury, show better attachment and proliferation on CHI- g-PLA and HMB surface, especially switched to PLA, as compared to the parent polymers. HDF cells also show improved collagen production on these surfaces as shown by Sirius red assay and immunofluorescence imaging. AFM images of HDF cells on these surfaces show that they interact with the substrates via focal adhesions. Macrophages on the other hand showed lowered viability on the HMB surface, especially switched to PNVP. Hence, the HMB is a biocompatible material suitable as skin regeneration template with lowered immunogenicity. CHI-g-PLA microfibers, made by touch spinning technique, also supported the growth of HDF cells. This provides scope for development of microfibrous biocompatible scaffolds made of CHI-g-PLA and HMB for dermal regeneration.

Indexing (document details)
Advisor:
Commitee:
School: University of the Sciences in Philadelphia
Department: Pharmaceutics
School Location: United States -- Pennsylvania
Source: DAI-B 79/12(E), Dissertation Abstracts International
Source Type: DISSERTATION
Subjects: Polymer chemistry, Pharmaceutical sciences, Materials science
Keywords: Biocompatible materials, Chitosan, Human dermal fibroblasts, Hybrid molecular brushes, Skin wound healing, Surface adaptability
Publication Number: 10904830
ISBN: 9780438157347
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