Resistance of Oil-Infused PDMS with Different Macroporosities Against Bacterial Attachment

Abstract

SLIPS are known for their self-repairing properties, repellency against water and complex fluids, and low-fouling properties. Here, a series of environmentally benign, non-fluorinated liquid paraffin-infused porous PDMS networks with varying porosities is created. Different homogenous and heterogeneous bulk structures and varying interfacial roughness are fabricated by sugar and salt templating. The macroporous PDMS exhibited high oil infusion efficiency and stability, particularly pronounced for the finer bulk structures. Under dynamic conditions, all lubricant-infused samples showed reduced bacterial attachment of Escherichia coli, Pseudomonas fluorescens, and Bacillus subtilis compared to butyl methacrylate references. The nature of the bulk structure turned out to have a dominating influence on the fouling resistance. A fine homogeneous bulk structure and an interface with few pores performed best against bacterial fouling. Compared to the other two organisms, colonization by Pseudomonas fluorescens is most effectively reduced on all paraffin-infused surfaces, indicating that the presence of the lubricant itself is more important than the structure of the PDMS scaffold. The different fouling preferences of the freshwater bacteria are discussed based on their rhamnolipid expression levels. The described macroporous paraffin-infused PDMS scaffolds that can be fabricated in any shape are promising as low-fouling materials for a wide range of medical applications.