Bioinspired lubricant-infused surfaces exhibit various unique properties attributed to their liquid-like and molecularly smooth nature. Excellent liquid repellency and "slippery" properties, self-healing, antiicing, anticorrosion characteristics, enhanced heat transfer, antibiofouling, and cell-repellent properties have been already demonstrated. This progress report highlights some of the recent developments in this rapidly growing area, focusing on properties of lubricant-infused surfaces, and their emerging applications as well as some future challenges.coatings. [8] In order to solve the abovementioned limitations of traditional superhydrophobic and superoleophobic surfaces, Quéré, Aizenberg, and Varanasi proposed bioinspired slippery liquidinfused porous surface (SLIPS) or lubricant-impregnated surfaces combining the mechanical stability of a solid substrate with the liquid-like properties and molecularly smoothness of the lubricant interface. [9a-d] It should be noted that stabilization of a lubricant layer on solid surfaces by forming a thin polymer film that can be swollen in the lubricant was introduced in 1988 by Karakelle and Zdrahala from Bekton, Dickinson and Company.[9e] They also demonstrated excellent long-term stability, liquid repellency, and proposed various medical applications of lubricant-impregnated surfaces. SLIPSs mimic the Nepenthes pitcher plant surface, [10] which is textured and can be lubricated with an aqueous solution. [11] The unique slippery character of the [9a] Nepenthes pitcher plant's surface resulting from water lubrication helps it capture insects sliding into its interior. To mimic the Nepenthes pitcher plant surface, a lubricating hydrophobic liquid can be infused into different hydrophobic porous or rough substrates to form SLIPS. [9] By matching the surface energy of the underlying porous substrate and the hydrophobic lubricant, the liquid can be stabilized on the surface of the substrate to form SLIPS. [9a] Depending on the impregnated lubricant, SLIPSs possess excellent repellency and drop mobility to a broad range of liquids including low surface tension liquids, and complex fluids such as blood or cell medium. [9a] This liquid repellency as well as SLIPS′ self-healing properties are due to the mobility of the lubricant trapped inside the porous surface structures. [12] Lubricant-infused surfaces demonstrated icephobic, stainresistant, biofilm-or cell-repellent or marine antibiofouling properties as well as tolerance to high pressure and transparency. [9,13] All of these unique properties make SLIPS interesting for the development of novel functional materials and various practical applications.The goal of this progress report is not to comprehensively review this broad and dynamic research field but rather highlight selected important aspects that have been less reviewed so far despite their potential. Some important and related papers could not be cited due to the length limitations. We also refer readers to several excellent reviews covering applications of ...

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Slippery lubricant-infused surfaces are composite materials consisting of a solid matrix permanently infused by a lubricant. Such surfaces have proved to be highly repellent to various liquids immiscible with the lubricant. Depending on the underlying surface chemistry, different lubricants can be used, including perfluorinated or alkylated oils. Here, we construct patterned slippery surfaces that consist of virtual channels permanently impregnated with an organic oil and surrounded by areas permanently impregnated with a perfluorinated oil. We demonstrate that water droplets preferentially occupy the organic-oil-lubricated virtual channels. Based on a simple model, we evaluate the forces acting on droplets crossing over to the regions impregnated with perfluorinated oil and show that the cloaking of the droplets plays an important role. We study the actuation of droplets in virtual oil-in-oil channels based on gravity and magnetic fields. Finally, we construct a variety of organic-oil-lubricated channel architectures permitting droplet sorting according to size. We believe that this novel approach for the formation of virtual all-liquid surface-tension-confined channels based on lubricant-infused surfaces, channel networks, or patterns will advance the field of droplet-based microfluidics. The approach presented can be potentially useful for applications in biotechnology, diagnostics, or analytical chemistry.

Here we demonstrate a method to pattern liquids of varying surface tension and composition into droplets by utilizing slippery liquid-infused surfaces prepared on chemically-patterned substrates. We study the capability of different liquids to displace the lubricant from higher surface energy regions and show that both high and low surface tension liquids can imbibe the polymer, thereby forming droplets sharply following underlying surface energy patterns. For all liquids tested, droplet arrays of arbitrary shapes of each liquid were formed with precision down to 50 µm. By changing the chemical patterning from fluorinated to aliphatic groups, patterns of mineral and silicone oils were created. Finally, we demonstrate formation of two-dimensional micropatterns of three-phase liquid systemsfluorinated, organic, and aqueous phases. Liquid patterning on solid surfaces is an essential process in micro-and nano-fabrication. It has been used for microelectromechanical systems (MEMS)-fabrication, [1],[2],[3] microfluidicdevice design [4],[5] bio-scaffold creation, [6] or high-throughput screening efforts.

In pharmaceutical research and development, cell‐based assays are primarily used with readout that rely on fluorescence‐based and other label‐dependent techniques for analysis of different cellular processes. Superhydrophobic–hydrophilic droplet microarrays (DMA) and matrix‐assisted laser desorption/ionization (MALDI) mass spectrometry (MS) have recently emerged as key technologies for miniaturized high‐throughput cell assays and for label‐free molecular high‐content drug profiling, respectively. Here, nanoliter‐scale cell assays are integrated on DMAs with MALDI–MS imaging (MALDI–MSI) approaches to a droplet microarray–mass spectrometry imaging (DMA–MSI) platform. Using A549 lung cancer cells, concentration‐response profiling of a pharmaceutical compound, the fatty acid synthase inhibitor GSK2194069, are demonstrated. Direct cell culture on DMAs enables combination of microscopy and high speed, high molecular content analysis using MALDI–MSI. Miniaturization of array spots down to 0.5 mm confining 40 nL droplets allows for MALDI imaging analysis of as few as ten cells per spot. Partial automation ensures a fast sample preparation workflow. Taken together, the integrated DMA–MSI platform that combines MALDI‐MSI, as a label‐free analytical readout, with the miniaturized droplet microarray platform is a valuable complement to high throughput cell‐based assays technologies.