Summary: A study is presented on ink‐jet printing polymers, aiming at library generation for combinatorial material science applications, using (optimized) micropipettes. Solvents were successfully ink‐jet printed, up to 160 mPa s viscosity. Printability of polymer solutions decreases strongly with $\overline M _{\rm w}$ and polymer concentration, due to elastic stresses originating from elongational flow in the pipette nozzle. The feasibility of ink‐jet printing to generate arrays of polymer dots and films was demonstrated.An array of square films is shown that was created by printing a solution containing polydisperse polystyrene in acetophenone and 0.1% disperse red 1 to improve the contrast.magnified imageAn array of square films is shown that was created by printing a solution containing polydisperse polystyrene in acetophenone and 0.1% disperse red 1 to improve the contrast.

There is considerable interest in creating convenient biosensing platforms that couple the capabilities of biology for selective detection with the power of electronics for signal transduction. Here, the capabilities of a polymeric fiber for facile biofunctionalization is coupled with the signal transduction capabilities of a conducting wire to generate a hybrid platform that can be viewed as either a biofunctionalized wire or a conducting fiber. Integral to this hybrid platform is the interface material chitosan that enables simple electrical signals to be employed to biofunctionalize conducting wires. Specifically, we use cathodic signals to direct chitosan to electrodeposit onto gold wires and anodic signals to conjugate proteins (e.g., for biosensing) to the chitosan-coated wire. In addition, the chitosan-coating is permeable to small molecules, which allows for the electrical detection of electrochemically active compounds that are either present in the external environment or generated by a biofunctionalized chitosan coating. The capabilities for biofunctionalization and transduction are demonstrated for the detection of glucose by chitosan-coated wires functionalized with the enzyme glucose oxidase. Chitosan-coated wires (or alternatively conducting chitosan fibers) are a simple platform that may permit multiplexed biosensing outside the laboratory.

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