Soft-matter nanofluidic and bioelectronic systems integrated to solid-state devices

Summary form only given. We develop nanoscale soft-matter devices with complex functionalities inspired from biological systems. The fabrication and large-scale integration of these systems are critically dependent on micromachined solid-state substrates and devices such as structural, MEMS, microelectronic, and microfluidic components. Specifically, we have developed micromanipulation methods for the construction of liquid crystal (lipid bilayer) nano-networks of high geometrical and topological complexity. The networks consist of surface-immobilized unilamellar vesicles (/spl sim/5-25 /spl mu/m in diameter) conjugated with nanotubes 50-150 nm in radius. The membrane composition (e.g. lipids, transporters, receptors, and catalytic sites), and container contents (e.g. catalytic particles, organelles, and reactants) can be controlled on the single-container level allowing complex chemical programming of networks. Fluid movement in nanotubes and materials exchange between conjugated containers can be obtained by using either Marangoni flows (transport driven by a moving boundary caused by gradients in surface free energy) or by electrophoresis. As an example, transport of individual DNA molecules in nanotubes is shown. The photon counts/DNA is directly related to DNA concentration and due to the strong confinement, the burst profiles can yield information on the conformation of migrating DNA molecules. Thus, networks of nanotubes and vesicles serve as a platform to build nanofluidic devices operating with single molecules and particles and offers new opportunities to study conformational dynamics and reaction kinetics in confined biomimetic compartments as well as providing nanotechnological devices for e.g. DNA separation and quantitation. The networks can also be used to construct computational and complex sensor systems that also can be integrated to living cells. Finally, a recent work on cell-based biosensors integrated with microfluidic devices is presented. In particular, a microfluidics-patch clamp platform for performing high-throughput screening and rapid characterization of weak affinity ion-channel-ligand interactions, and a chip-based electroporation platform for identification of intracellular proteins, and characterization of protein-ligand interactions are demonstrated.