H18 - Investigating the PSS/PDADMAC Coacervate System for Wound Healing Applications

Introduction: : Although it has come a long way, the treatment of chronic wounds continues to be limited by infection, often caused by a lack of vascularization, which prevents wound oxygenation. Drug delivery and pain management in wound care also remain unresolved, as current treatments are non-specific and often lead to unwanted side effects. To address these problems, complex coacervates are being explored due to their potential for biocompatibility and processability. Highly tunable, coacervates closely mimic cellular environments and are commonly non-toxic. Polymer coacervates made from poly(styrene sulfonate) (PSS) and poly(diallyldimethylammonium chloride) (PDADMAC), when appropriately engineered, offer a dynamic opportunity. Because of its robustness, the PSS/PDADMAC coacervate system can be formed into vascular-like networks with the aptitude for encouraging wound oxygenation via direction of cellular organization. Due to its tunability, the system is also well-suited for the integration of additional materials for drug delivery purposes, allowing personalized treatment options. In our research, the primary objective is to investigate the potential of the PSS/PDADMAC coacervate system for improved wound healing applications.

Materials and

Methods: : Liquid complex coacervate was formed using diluted PSS, PDADMAC, and potassium bromide (KBr). Biomaterials were constructed from the liquid coacervate via simple film deposition and solution blow spinning (SBS), and rinsed in deionized water to remove salts. For cell culture use, materials were sterilized using 70% ethanol solution. Experiments were completed for physical and mechanical material characterization, including light and electron microscopy, rheometry, and turbidity. To investigate cell viability, attachment, and proliferation, bone marrow-derived rat mesenchymal stem cells (MSCs) were cultured on the solid coacervate materials. DNA assay and alamar blue staining were performed to quantify cell metabolic activity and proliferation in response to the complex coacervate substrate. Cytoskeletal staining was also performed to analyze cell attachment and morphology.

Results, Conclusions, and Discussions:: Results and

Discussion:
Through investigation into various material formation and deposition strategies, multiple aspects of the PSS/PDADMAC complex coacervate system were optimized for ideal cell behavior, including charge ratio, total polymer concentration, and method of material deposition. Physical and mechanical properties were assessed to better understand the system as a whole and its applications to the field of wound healing. Using MSCs as a model system, the material was further able to be characterized in terms of its interactions with living cells, providing insight into the wound-coacervate interface. Current efforts focus on quantifying these characteristics to get a deeper understanding of the cell-coacervate dynamics.

Conclusion:
Our findings expand the understanding of cell–coacervate interactions and provide a detailed characterization of the PSS/PDADMAC coacervate system. Through our research, we have further investigated the use of complex coacervation as a tunable means for wound healing. These findings guide our future work on wound healing technologies, including studies on biodegradability and crosslinking methods. In future studies, we plan to examine the antibacterial potential of the PSS/PDADMAC coacervate system, supported by previous reports (Kurtz et al., 2019).

Acknowledgements and/or References (Optional):: References
Kurtz IS, Sui S, Hao X, Huang M, Perry SL, Schiffman JD. Bacteria-Resistant, Transparent, Free-Standing Films Prepared from Complex Coacervates. ACS Appl Bio Mater. 2019 Sep 16;2(9):3926-3933. doi: 10.1021/acsabm.9b00502. Epub 2019 Aug 13. PMID: 31579306; PMCID: PMC6774644.