(182ai) Biocompatibility of Polyampholyte Polymers for Tissue Engineering Applications

Polyampholyte polymers have shown tremendous potential in recent years as a tissue engineering platform. Polyampholytes are a subclass of zwitterionic materials created from both positively and negatively charged monomer subunits. Previous studies have shown them to exhibit unique properties such as resistance to non-specific protein adsorption, which minimizes the foreign body response [1]. Although they demonstrate resistance to protein adsorption, they are capable of covalently attaching biomolecules. Additionally, these polymers have tunable mechanical properties by modifying cross-linker density, cross-linker length and underlying monomer composition [2]. Prior studies evaluated short term adhesion of MC3T3-E1 osteoblast-type cells via covalently bound protein. A more comprehensive biocompatibility investigation is necessary prior to evaluating the role of polyampholytes in aiding tissue regeneration in vivo.

In this work, we further explore and improve the biocompatibility of polyampholyte polymers composed of positively charged [2-(acryloyloxy) ethyl] trimethyl ammonium chloride (TMA) and negatively charged 2-carboxyethyl acrylate (CAA) crosslinked with triethylene glycol dimethacrylate (TEGDMA). The hydrogel solution was analyzed before and after free radical polymerization occurred. Based on findings, the buffer formulation was modified to allow for longer term biocompatibility. Following the adjustment to the formulation, it was verified that non-fouling and biomolecule conjugation properties were preserved. Biocompatibility was then studied through short-term (2 hour) adhesion and long term (24 hours and 5 day) proliferation of MC3T3-E1 cells. The change in electrostatic behavior and counter ion interactions will be discussed as they relate to the improved biocompatibility performance.

1. Schroeder, M.E., et al., Multifunctional Polyampholyte Hydrogels with Fouling Resistance and Protein Conjugation Capacity. Biomacromolecules, 2013. 14(9): p. 3112-3122.
2. Mariner, E., et al. Impacts of Cross-Linder Chain Length on the Physical Properties of Polyampholyte Hydrogels. Submitted. 2019.