Water on superhydrophilic surfaces spreads or is absorbed very quickly, and exhibits water contact angles close to zero. We encounter superhydrophilic materials in our daily life (e.g., paper, sponges, textiles) and they are also ubiquitous in nature (e.g., plant and tree leaves, Nepenthes pitcher plant). On the other hand, water on completely non-wettable, superhydrophobic surfaces forms spherical droplets and rolls off the surface easily. One of the most well-known examples of a superhydrophobic surface is the lotus leaf. Creating novel superhydrophobic surfaces has led to exciting new properties such as complete water repellency, self-cleaning, separation of oil and water, and antibiofouling. However, combining these two extreme states of superhydrophilicity and superhydrophobicity on the same surface in precise two-dimensional micropatterns opens exciting new functionalities and possibilities in a wide variety of applications from cell, droplet, and hydrogel microarrays for screening to surface tension confined microchannels for separation and diagnostic devices. In this Progress Report, we briefly describe the methods for fabricating superhydrophilic-superhydrophobic patterns and highlight some of the newer and emerging applications of these patterned substrates that are currently being explored. We also give an outlook on current and future applications that would benefit from using such superhydrophilic-superhydrophobic micropatterns.

High‐density cell microarrays based on superhydrophilic microspots separated by superhydrophobic barriers have been realized. The microspots absorb water solutions, while the barriers prevent cross‐contamination, thus allowing the spots to be used as reservoirs for transfection mixtures and preventing cell proliferation and cell migration between the microspots. The picture shows four cell types after two days of culturing on the microarray.

High throughput screening of live cells is a crucial technology that allows for the parallel functional evaluation of the influence of multiple factors on cell behavior and phenotype. In the last years due to the rapid expansion of bioinformatics and genomic tools, increasing throughput and decreasing screening costs became an essential milestone for research in this field. In current study we present a Droplet-Array (DA) Sandwich Technology add reagents at any time point and retrieve the cells after culturing; (h) compatibility with standard screening microscopes. In the current study we demonstrate that DA Sandwich Chip can be applied for performing drug screens and gene overexpression experiments with 3 commonly used adherent cell lines and therefore can be adopted for various cell-based screening applications.

No abstract

We describe a one-step method for creating thousands of isolated pico- to microliter-sized droplets with defined geometry and volume. Arrays of droplets are instantly formed as liquid moves along a superhydrophilic-superhydrophobic patterned surface. Bioactive molecules, nonadherent cells, or microorganisms can be trapped in the fully isolated microdroplets for high-throughput screening, or in hydrogel micropads for screening in 3D microenvironments.