Slippery Liquid‐Infused Porous Surfaces that Prevent Microbial Surface Fouling and Kill Non‐Adherent Pathogens in Surrounding Media: A Controlled Release Approach

Abstract

Many types of slippery liquid-infused porous surfaces (or ‘SLIPS’) can resist adhesion and colonization by microorganisms. These ‘slippery’ materials thus offer new approaches to prevent fouling on a range of commercial and industrial surfaces, including biomedical devices. However, while SLIPS can prevent fouling on surfaces to which they are applied, they can currently do little to prevent the proliferation of non-adherent (planktonic) organisms, stop them from colonizing other surfaces, or prevent them from engaging in other behaviors that could lead to infection and associated burdens. Here, we report an approach to the design of multi-functional SLIPS that addresses these issues and expands the potential utility of slippery surfaces in antimicrobial contexts. Our approach is based on the incorporation and controlled release of small-molecule antimicrobial agents from the porous matrices used to host infused slippery oil phases. We demonstrate that SLIPS fabricated using nanoporous polymer multilayers can prevent short- and longer-term colonization and biofilm formation by four common fungal and bacterial pathogens (Candida albicans, Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus), and that the polymer and oil phases comprising these materials can be exploited to load and sustain the release of triclosan, a model hydrophobic and broad-spectrum antimicrobial agent, into surrounding media. This approach both improves the inherent anti-fouling properties of these materials and endows them with the ability to efficiently kill planktonic pathogens. Finally, we show that this approach can be used to fabricate dual-action SLIPS on complex surfaces, including the luminal surfaces of flexible catheter tubes. This strategy has the potential to be general; we anticipate that the materials, strategies, and concepts reported here will enable new approaches to the design of slippery surfaces with improved anti-fouling properties and open the door to new applications of slippery liquid-infused materials that host or promote the release of a variety of other active agents.

Slippery Liquid-Infused Porous Surfaces that Prevent Bacterial Surface Fouling and Inhibit Virulence Phenotypes in Surrounding Planktonic Cells

“…13,21 Infusion of silicone oil into the decylamine-functionalized multilayers yielded SLIPS that exhibited water droplet sliding angles of ≤ 10°, in agreement with our past studies (Table 1). 13,21 …”

“…13,21,56–58 After film fabrication, these reactive multilayers were treated with n -decylamine to functionalize residual azlactones remaining in the films with hydrophobic alkyl groups (Figure 1A) 13,21,57 and render them more chemically compatible with silicone oil. 13,21 Infusion of silicone oil into the decylamine-functionalized multilayers yielded SLIPS that exhibited water droplet sliding angles of ≤ 10°, in agreement with our past studies (Table 1). 13,21 …”

“…5,9,15 Several recent reports reveal SLIPS to be a promising platform for the development of new anti-biofouling interfaces for biological and environmental applications. 9,14,16–21 Indeed, SLIPS have been reported to resist fouling by a broad range of organisms, including clinically important bacterial 14,16,17,21 and fungal 21 pathogens, marine barnacle cyprids, 19 and mammalian cells. 18,20,21 …”

“…21 In that work, we leveraged the properties of a porous polymer matrix and an infused silicone oil phase to sustain the long-term release of the model small-molecule microbicidal agent triclosan. That study demonstrated that triclosan could be readily incorporated into SLIPS without impacting their anti-fouling properties, and that the slow release of triclosan could kill planktonic Candida albicans effectively and improve the overall antifouling and antifungal properties.…”

“…That study demonstrated that triclosan could be readily incorporated into SLIPS without impacting their anti-fouling properties, and that the slow release of triclosan could kill planktonic Candida albicans effectively and improve the overall antifouling and antifungal properties. 21 Because triclosan is a broad-spectrum antibiotic, it is likely that this approach could also be used to design multi-functional SLIPS that also kill planktonic bacteria. We note, however, that the use of triclosan and other cytotoxic drugs (e.g., antibiotics) have several disadvantages in applied contexts, perhaps most notably the fact that the widespread use of these agents has led to evolved resistance in many clinically relevant pathogens.…”