Tethered-liquid perfluorocarbons (TLPs) are a class of liquid-infused surfaces with the ability to reduce blood clot formation (thrombosis) on blood-contacting medical devices. TLP comprises a tethered perfluorocarbon (TP) infused with a liquid perfluorocarbon (LP); this LP must be retained to maintain the antithrombotic properties of the layer. However, the stability of the LP layer remains in question, particularly for medical devices under blood flow. In this study, the lubricant thickness is spatially mapped and quantified in situ through confocal dual-wavelength reflection interference contrast microscopy. TLP coatings prepared on glass substrates are exposed to the flow of 37% glycerol/water mixtures (v/v) or whole blood at a shear strain rate of around 2900 s–1 to mimic physiological conditions (similar to flow conditions found in coronary arteries). Excess lubricant (>2 μm film thickness) is removed upon commencement of flow. For untreated glass, the lubricant is completely depleted after 1 min of shear flow. However, on optimized TLP surfaces, nanoscale films of lubricants (thickness between 100 nm and 2 μm) are retained over many tens of minutes of flow. The nanoscale films conform to the underlying structure of the TP layer and are sufficient to prevent the adhesion of red blood cells and platelets.
J.K.H. acknowledges the Australian Government Research Training Program (RTP) Scholarship, the University of Sydney RTP Supplementary Scholarship, the University of Sydney Completion Stipend Scholarship, the Heart Research Institute, the University of Sydney Nano Institute, Charles Perkins Centre, and the Surface Coatings Association Australia Scholarship for financial support. J.K.H. also acknowledges the University of Sydney Charles Perkins Centre EMCR Seed Funding for funding support. C.N. acknowledges the Australian Research Council for funding (FT180100214). A.W. acknowledges funding from the Clive and Vera Ramaciotti Foundations Health Investment Grant, National Heart Foundation of Australia Vanguard Grant (103004), and NSW Health. D.D. was supported by KAUST start-up fund (BAS/1/1416-01-01). I.J.G. acknowledges funding from AINSE (ECRG). The authors acknowledge the facilities and the scientific and technical assistance of the Microscopy Australia node at the Australian Centre for Microscopy & Microanalysis (ACMM), Sydney Microscopy and Microanalysis at the University of Sydney.