Functional Colloids from Amphiphilic Polymer Assemblies and Peptides/Polypeptides

• Main Author: Zholobko, Oksana
• Format: Others
• Published: North Dakota State University 2019
• Online Access: https://hdl.handle.net/10365/29963

The use of responsive polymers, where even minor changes in one of the macromolecular characteristics triggered by the external stimuli can cause drastic changes in the material function or performance, is widely studying area of research. Formation of the thermodynamically stable polymer-peptide colloids, such as mixed micellar assemblies or polymer-enzyme conjugates, loading capacity of the colloids, and cargo activity all depend on the macromolecular interactions within the peptide/polypeptide-polymer system. The goal of this work is to investigate interactions between range of new polymers and various cargo molecules and determine whether those interactions affect the physicochemical properties of the resulted colloids. For this purpose, two types of colloid systems were explored: i) peptide-loaded invertible micellar assemblies (IMAs), formed using hydrophobic interactions between amphiphilic invertible polymers (AIP) and peptides (HA, V5, or peptide-based vaccine), and ii) polymeric cellulosomes made from polymer ligand (PL), copolymer of glycidyl methacrylate (GMA) and poly(ethylene glycol) methyl ether methacrylate (PEGMA) and mixture of cellulases, using covalent bonding. The purpose of the research was to evaluate if colloids properties are affected by changes in responsive polymer characteristics as well as if the developed macromolecular structure and composition need further synthetic modification/optimization. AIP-related part of this dissertation is focused on i) understanding of interaction between peptides and AIPs, and formation of mixed micellar assemblies; ii) further behavior of cargo peptide molecules in the micellar interior under the AIP conformational changes, triggered by IMAs localization at polar and nonpolar interface; iii) evaluation of the impact of IMAs on model lipid membrane diffusivity and permeability. Besides, AIP-peptide assemblies were tested in vitro and in vivo in order to evaluate the cargo delivery, antibody response, and immunity protection in vaccinated pigs against Swine influenza viruses (SIV). To explore the feasibility of covalent bonding in formation of responsive polymer-based colloids, enzyme-polymer conjugates (EPCs) were designed and their enzymatic catalytic activity for the biomass hydrolysis was further tested. The effect of conjugation on catalytic activity, conjugation efficiency, glucose inhibition effect, type of substrate, and type of biomass pretreatment were evaluated and compared to free enzymes. === North Dakota. Department of Commerce === National Science Foundation (U.S.)