Solution Blow Spinning of Complex Coacervates for Wound Healing Applications

Surgical site infections (or SSIs) are typically caused by bacteria such as Staphylococcus, Streptococcus, and Pseudomonas. Most SSIs—depending on severity—can be treated with antibiotics, however delay in treatment of SSIs can lead to sepsis and septic shock which can be deadly. According to the CDC, the number of SSI events associated with in-patient surgery has continued to increase from 2015 to now, despite advances in infection prevention practices, suggesting a need for solution in diagnosing the infection. This project demonstrates proof of concept for a rapid, visual indicator of bacterial infection to detect SSIs faster and in-situ. We use a complex coacervation—liquid-liquid phase separation phenomenon—system of a poly(diallyldimetheylammonium chloride) (PDADMAC) and poly(stryrene sulfonate) (PSS) in potassium bromide solution. Via a technique called solution blow spinning with a commercial airbrush, we can spray the complex coacervate onto a substrate mimicking a bandage sprayed on a wound in-situ. Variables including distance to the substrate, air pressure, salt concentration, and static versus sweeping airbrush motion impact the morphology of resulting droplets. We also test the encapsulation of small molecule cargo like fluorescent dyes and pH indicators in the system, for the proposed application of visual indication of pH flux due to bacteria presence. Future research using carboxymethyl cellulose (CMC) as a polyanion to complex with PDADMAC can improve the biocompatibility of the system. Our research on solution blow spraying complex coacervates with pH indicator encapsulation proves the possibility of a sprayable bandage to improve effective diagnoses of surgical site infection.