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Protein patterns of different shapes and densities are useful tools for studies of cell behavior and to create biomaterials that induce specific cellular responses. Up to now the dominant techniques for creating protein patterns are mostly based on serial writing processes or require templates such as photomasks or elastomer stamps. Only a few of these techniques permit the creation of grayscale patterns. Herein, the development of a lithography system using a digital mirror device which allows fast patterning of proteins by immobilizing fluorescently labeled molecules via photobleaching is reported. Grayscale patterns of biotin with pixel sizes in the range of 2.5 μm are generated within 10 s of exposure on an area of about 5 mm(2) . This maskless projection lithography method permits the rapid and inexpensive generation of protein patterns definable by any user-defined grayscale digital image on substrate areas in the mm(2) to cm(2) range.

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We describe a generic microfluidic interface design that allows the connection of microfluidic chips to established industrial liquid handling stations (LHS). A molding tool has been designed that allows fabrication of low-cost disposable polydimethylsiloxane (PDMS) chips with interfaces that provide convenient and reversible connection of the microfluidic chip to industrial LHS. The concept allows complete freedom of design for the microfluidic chip itself. In this setup all peripheral fluidic components (such as valves and pumps) usually required for microfluidic experiments are provided by the LHS. Experiments (including readout) can be carried out fully automated using the hardware and software provided by LHS manufacturer. Our approach uses a chip interface that is compatible with widely used and industrially established LHS which is a significant advancement towards near-industrial experimental design in microfluidics and will greatly facilitate the acceptance and translation of microfluidics technology in industry.

future applications. To obtain biofunctional surfaces, amongst others the mode of immobilization, the distribution of the tethered molecules on a micrometer scale and the microtopography of the substrate need to be tailored. [ 2 ] So far, in vitro studies were mainly carried out on planar surfaces. To permit highly miniaturized and thus parallelized assays with low compound consumption, for instance to test the response of cells to effector molecules, microarrays of protein or ligandcoated spots ranging from 100-500 μ m in diameter can be produced by microcontact printing, spotting or patterning with microfl uidic networks. [ 3 ] To investigate the role of surface bound chemical cues on cell behavior, often patterns of biomolecules, particularly proteins, such as growth factors or cell adhesion proteins, have to be created. Biologically active molecules can be immobilized on chemically modifi ed patterns on the substrate. As in the production of microarrays, spatially-defi ned patterns of functional groups have been generated by microcontact printing [ 4 ] and microfl uidic networks, [ 5 ] but they can also be drawn by dip pen nanolithography (DPN) using the tip of a probe controlled by an atomic force microscope, [ 6 ] or created by mask-based lithography with biocompatible resists. [ 7 ] Another option to obtain patterns of functional groups is chemical vapor deposition (CVD) polymerization of [2.2]paracyclophane derivatives. [ 8 ] This

Arrays with polymer-coated acoustic sensors, such as surface acoustic wave (SAW) and surface transverse wave (STW) sensors, have successfully been applied for a variety of gas sensing applications. However, the stability of the sensors’ polymer coatings over a longer period of use has hardly been investigated. We used an array of eight STW resonator sensors coated with different polymers. This sensor array was used at semi-annual intervals for a three-year period to detect organic solvent vapors of three different chemical classes: a halogenated hydrocarbon (chloroform), an aliphatic hydrocarbon (octane), and an aromatic hydrocarbon (xylene). The sensor signals were evaluated with regard to absolute signal shifts and normalized signal shifts leading to signal patterns characteristic of the respective solvent vapors. No significant time-related changes of sensor signals or signal patterns were observed, i.e., the polymer coatings kept their performance during the course of the study. Therefore, the polymer-coated STW sensors proved to be robust devices which can be used for detecting organic solvent vapors both qualitatively and quantitatively for several years.

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