Study of V-V transfer in CD2Cl2 by laser-induced fluorescence experiments

Vibrational energy transfer between the fundamentals of CD₂Cl₂ is studied by laser-induced fluorescence experiments. The data obtained confirm the result and interpretation of former acoustic experiments which indicated an inefficient energy exchange between the lowest vibrational mode and the upper modes. The pτ value obtained for this V-V process is 60 μs Torr. Energy transfer between the upper modes is more efficient and the corresponding pτ values are smaller than 4 μs Torr for the modes investigated in this work.     

V—V,V—R,T transfer in triatomic molecules. Results for ONF

The laser-induced fluorescence technique is applied to study vibrational energy transfer in pure ONF. Different vibrational modes are excited using a TEA CO₂ laser and the rise and fall of ν₁, ν₂, and (ν₁ + ν₃) fluorescence is detected. These measurements yield a detailed picture of V—V exchange in the region of the fundamentals and V—R,T transfer to rotational and translational degrees of freedom. The relaxation behavior of ONF is compared with that of ONCI and other triatomic molecules.     

Applying microdroplets as sensors for label-free detection of chemical reactions

Despite its tremendous high-throughput screening capabilities, widespread applications of droplet-based microfluidics are still limited by the poor availability of appropriate analytical assays. Here we report on a novel sensor method that exploits the osmosis-driven change in droplet size as a quantitative and label-free marker for reactions inside the droplets. We present an analysis of the underlying mechanism and apply the method for monitoring metabolic activity at a single-cell level.     

Artificial Cytoskeleton Assembly for Synthetic Cell Motility

Imitation of cellular processes in cell-like compartments is a current research focus in synthetic biology. Here, a method is introduced for assembling an artificial cytoskeleton in a synthetic cell model system based on a poly(N-isopropyl acrylamide) (PNIPAM) composite material. Toward this end, a PNIPAM-based composite material inside water-in-oil droplets that are stabilized with PNIPAM-functionalized and commercial fluorosurfactants is introduced. The temperature-mediated contraction/release behavior of the PNIPAM-based cytoskeleton is investigated. The reversibility of the PNIPAM transition is further examined in bulk and in droplets and it could be shown that hydrogel induced deformation could be used to controllably manipulate droplet-based synthetic cell motility upon temperature changes. It is envisioned that a combination of the presented artificial cytoskeleton with naturally occurring components might expand the bandwidth of the bottom-up synthetic biology.