Click‐and‐Bond: Room‐Temperature and Solvent‐Free Bonding of Polymer‐Based Microfluidic Devices

The production of a new class of microfluidic devices built from thermoplastic materials has recently aroused interest in a high-volume and cost-effective fabrication of sensing devices. During device formation, the bonding of two slides, one containing the microchannels and another used as a non-modified capping layer, is generally performed at high temperature, high pressure, and/or employing organic solvents. Such bonding procedures, however, are not compatible with the use of slides pre-functionalized with biomolecules. Here a low-temperature, UV-light-free, and solvent-free bonding method for polymeric devices, based on poly-l-lysine (PLL) polymers modified with click-chemistry moieties is presented. The advantages obtained from the use of PLL and the appended complementary click-chemistry groups enable a fast adsorption of polymers onto the substrates at room temperature, followed by a fast and stable bonding between two complementarily functionalized slides under mild conditions. Bonded fluidic devices show a resistance to high fluid pressures well above those needed for practical application. The optimal density (2-5%) of reactive groups appended to PLL is assessed using lap shear tests. The here developed method achieves bonding at low temperature, which promises fabrication of microfluidic devices functionalized with biomolecules prior to the sealing process, applicable to a wide range of polymeric materials.