Skip to Main Content
 

Global Search Box

 
 
 
 

ETD Abstract Container

Abstract Header

Design and Synthesis of Multifunctional Polyesters with 'Peptide-Like' Pendant Groups

Abstract Details

, Doctor of Philosophy, University of Akron, Polymer Science.
Current biomaterials including polylactic acid have good mechanical and biodegradable properties.1 But they are devoid of functional groups that enable integration with the cellular environment. We have designed a platform of modular multifunctional polyesters with pendant functional groups that address the lack of functional cues in current biomaterials.2 The polyesters were synthesized at room temperature by carbodiimide-mediated polymerization of pendant functionalized diols and succinic acid.3 The pendant groups were designed to mimic the side chains of peptides. It was shown that the physical properties of the polyesters can be modulated over a wide range by the selection of pendant groups. In addition, orthogonal functionalization of the pendant groups with ligands such as fluorophores, poly (ethylene glycol) (PEG) or Arg-Gly-Asp (RGD) was shown. One specific application of functional polyester was the design of mussel inspired adhesives by incorporation of catechol groups into side chain of such polyesters. The first generation adhesive polyester showed the effect of 3,4-dihydroxyphenylalanine (DOPA) groups, but the adhesion strength on aluminum substrate decreased in wet conditions. The second generation adhesive polyester was a copolymer with soybean oil based monomer, coumarin and DOPA monomer. The polymer was viscous with a glass transition temperature of -50 °C. It showed good adhesion under both dry and wet conditions. Adhesion tests on porcine skin were also performed and the results demonstrated that our polymer had higher adhesion strength than the commercial fibrin glue. iv A second application was the fabrication of nanofiber mats through electrospinning for extended dual release of model drugs. The polymer contained 20% ketone side chain and the ketone group was used to conjugate with alkoxyamine derivative of rhodamine B through oxime bond. Two types of electrospun fiber mats were made. For one of them, two dyes (Rhodamine B and coumarin dye) were non-covalently encapsulated within the polymer fibers. For the other one, rhodamine B was covalently attached to the fibers, while coumarin dye was physically entrapped. For the fibers with non-covalently encapsulated dyes, the release of dyes over 90 days showed that the coumarin dye had a faster release profile compared to the rhodamine B dye. The release showed a three-phase profile for both dyes. The release was characterized by initial burst release over 7 days, followed by a plateau till day 55 and then an acceleration in rate till day 90. For the fibers where coumarin dye was encapsulated and rhodamine B was tethered, the release of coumarin dye was similar to the first one. The oxime bond of the covalently tethered rhodamine B was stable over 90 days, and there was no release of rhodamine B in 1×phosphate buffer saline(PBS) (pH = 7.4). The reason for limited release of covalently tethered rhodamine B is that oxime bonds are relatively stable under the experiment conditions, according to the studies by Raines and coworkers.4 Another project of the functional polyesters developed in this work was to study the differentiation of stem cell into osteoblasts. Three polymers with 40% of carboxylic (COOH), amine (NH2), or hydroxyl (OH) pendant groups, were synthesized. The polymers contained 10% of alkene in the backbone, which could be used for crosslinking. The three polymers were used for examining the differentiation of mouse pre-osteoblast cell lines (MC3T3) into osteoblasts. Alkaline Phosphatase (ALP) staining and ALP acitivity of v MC3T3 differentiated for 14 days were performed. From the ALP staining images, it was seen that the ALP production increased as COOH > blank > NH2 > TCPS (Tissue Culture treated Polystyrene) > OH. Alizarin Red staining and von Kossa staining of the MC3T3 differentiated for 21 days were performed to study the mineralization. Alizarin Red staining, polymer with COOH group demonstrated the largest influence on differentiation and the staining showed prominent mineralization. From von Kossa staining, it was seen that the polymers with COOH or NH2 provided the most differentiation. In these experiments, detailed differentiation experiments were not performed and the above results were obtained from preliminary staining protocols. In a further set of experiments, two polymers with the same amount of COOH but with different hydrophilicity were synthesized. They were used to encapsulate and release an osteoblast inducing peptide, osteoactivin (OA), from electrospun fibers. Both polymers were mixed with OA peptide for electrospinning. The release study showed different OA peptide release profiles from the two polymer fibers.
Abraham Joy (Advisor)
Mattew Becker (Committee Chair)
Coleen Pugh (Committee Member)
Ali Dhinojwala (Committee Member)
Younjin Min (Committee Member)

Recommended Citations

Citations

  • Xu, Y. (n.d.). Design and Synthesis of Multifunctional Polyesters with 'Peptide-Like' Pendant Groups [Doctoral dissertation, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1458084446

    APA Style (7th edition)

  • Xu, Ying. Design and Synthesis of Multifunctional Polyesters with 'Peptide-Like' Pendant Groups. University of Akron, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1458084446.

    MLA Style (8th edition)

  • Xu, Ying. "Design and Synthesis of Multifunctional Polyesters with 'Peptide-Like' Pendant Groups." Doctoral dissertation, University of Akron. Accessed MARCH 28, 2024. http://rave.ohiolink.edu/etdc/view?acc_num=akron1458084446

    Chicago Manual of Style (17th edition)