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

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This paper introduces the design of SoleSound, a wearable system designed to deliver ecological, audio-tactile, underfoot feedback. The device, which primarily targets clinical applications, uses an audio-tactile footstep synthesis engine informed by the readings of pressure and inertial sensors embedded in the footwear to integrate enhanced feedback modalities into the authors' previously developed instrumented footwear. The synthesis models currently implemented in the SoleSound simulate different ground surface interactions. Unlike similar devices, the system presented here is fully portable, and can therefore be utilized outside the laboratory setting. A first experimental evaluation indicates that the device can effectively modulate the perception of the ground surface during walking, thereby, inducing changes in the gait of healthy subjects.

Quantitative gait analysis enables clinicians to evaluate patient mobility and to diagnose neuromuscular disorders. The clinical application of gait analysis is currently limited by the high operating costs of gait laboratories. The use of instrumented footwear that performs out of the lab measurements on subjects' walking patterns is a promising way to overcome this limitation. Besides serving as assessment tools, such devices can also act as retraining tools that help regulate a patient's gait with acoustic or vibrotactile stimuli.

Surface modification is an essential tool in tissue engineering using synthetic biomaterial scaffolds. The authors report in this study a simple approach to modify the surface hydrophobicity, roughness and chemistry of electrospun polycaprolactone (PCL) fibers using a combination of oxygen plasma treatment, sodium hydroxide treatment and arginine–glycine–aspartic acid (RGD) immobilization. The modified surfaces were characterized using scanning electron microscopy, atomic force microscopy, water contact angle measurement and X-ray photoelectron spectroscopy (XPS). Plasma treatment decreased the water contact angle. Sodium hydroxide treatment further improved the hydrophilicity and increased the surface roughness. XPS analysis confirmed the presence of amide bonds on RGD-treated fibers. The enhancement of proliferation of ligament fibroblasts within 1 week of culturing on both the plasma- and sodium hydroxide–treated fibers was most likely due to improved wettability by the oxygen plasma treatment. The alignment and penetration of cells on PCL fibers suggested that these materials could be potential scaffold materials for the regeneration of fibrous tissues.