Liquid-infused structured surfaces with exceptional anti-biofouling performance

Abstract

Bacteria primarily exist in robust, surface-associated communities known as biofilms, ubiquitous in both natural and anthropogenic environments. Mature biofilms resist a wide range of antimicrobial treatments and pose persistent pathogenic threats. Treatment of adherent biofilm is difficult, costly, and, in medical systems such as catheters or implants, frequently impossible. At the same time, strategies for biofilm prevention based on surface chemistry treatments or surface microstructure have been found to only transiently affect initial attachment. Here we report that Slippery LiquidInfused Porous Surfaces (SLIPS) prevent 99.6% of Pseudomonas aeruginosa biofilm attachment over a 7-d period, as well as Staphylococcus aureus (97.2%) and Escherichia coli (96%), under both static and physiologically realistic flow conditions. In contrast, both polytetrafluoroethylene and a range of nanostructured superhydrophobic surfaces accumulate biofilm within hours. SLIPS show approximately 35 times the reduction of attached biofilm versus best case scenario, state-of-the-art PEGylated surface, and over a far longer timeframe. We screen for and exclude as a factor cytotoxicity of the SLIPS liquid, a fluorinated oil immobilized on a structured substrate. The inability of biofilm to firmly attach to the surface and its effective removal under mild flow conditions (about 1 cm∕s) are a result of the unique, nonadhesive, "slippery" character of the smooth liquid interface, which does not degrade over the experimental timeframe. We show that SLIPS-based antibiofilm surfaces are stable in submerged, extreme pH, salinity, and UV environments. They are low-cost, passive, simple to manufacture, and can be formed on arbitrary surfaces. We anticipate that our findings will enable a broad range of antibiofilm solutions in the clinical, industrial, and consumer spaces.antifouling surfaces | biofilm resistance | slippery materials | surface engineering

A colloidoscope of colloid-based porous materials and their uses

“…Another type of repellent surface circumvents these issues by using low surface energy lubricant oil infiltrated into a roughened surface ( Figure 12D). 217 Through capillary forces and matching chemistry between the oil and solid surface, the liquid forms a thermodynamically stable wetted state. A second immiscible liquid slides off the surface with ease.…”

“…[226][227][228] These omniphobic coatings not only repel complex liquids such as blood and crude oil, but they can also prevent bacterial biofilm formation, for example in catheters where patients are at risk for hospitalacquired infections. 217 Inverse opals can be infiltrated with a lubricant to create these liquid-infused surfaces. For example, Vogel et al templated silica using colloidal monolayers on a glass surface ( Figure 13B).…”

Transparency and damage tolerance of patternable omniphobic lubricated surfaces based on inverse colloidal monolayers

“…To maintain stable repellency, such a surface needs to be optimized in a way that the lubricant layer is not displaced from the solid's surface: if the free energy of the solid/lubricant/liquid system is minimal for the situation where the test liquid resides on the lubricant layer without replacing it, the liquid/liquid interface effectively eliminates pinning points, leading to superrepellent surfaces with extremely low sliding angles-even for liquids with very low surface tensions. Additionally, the fluid nature of the interface possesses self-healing characteristics, allows for remarkable pressure-stability 19 and has been shown to effectively prevent the attachment of bacteria 20 and ice 21 , thus overcoming many of the challenges of conventional repellent surfaces.…”

Time-Dependent Wetting Behavior of PDMS Surfaces with Bioinspired, Hierarchical Structures

“…In addition to the hierarchical surface features, 4 the mechanical robustness of sand dollars inspired us to employ them as templates for PDMS; it would be quite difficult to fabricate such textures via microfabrication techniques. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 5 PDMS films were inspired by the Nepenthes pitcher plant, 13 shark skins, 14 and bristles of echinoderms; 15 cell-infused sand dollars (Clypeaster subdepressus) were used as scaffolds for bone regeneration, 16,17 and sea urchin bioskeletons have been exploited to create macroporous gold. 18 Techniques of microfabrication have also been employed to create bio-inspired surfaces, however, non-orthogonal hierarchical features in three dimensions are very difficult to achieve and scale up.…”