Electropolymerized molecularly imprinted polymer films of a bis-terthiophene dendron: folic acid quartz crystal microbalance sensing

Colloidally templated two-dimensional conducting polymer arrays and SAMs: binary composition patterning and chemistry

A facile approach and strategy toward binary-composition, two-dimensional (2D) patterned surfaces of conducting polymer periodic arrays, together with thiol self-assembled monolayers (SAMs) is described. The method involved a Langmuir-Blodgett (LB)-like deposition of latex microsphere particles, electropolymerization via cyclic voltammetric (CV) techniques, and self-assembly of an amphiphile. The LB-like technique enabled the monolayer deposition of different sizes of polystyrene (PS) particles in hexagonal packing arrangement on planar substrates. Combining the LB-like method with CV electropolymerization is advantageous because it provides deposition control of a polymer interconnected network, controlled composition ratio of polymer and SAMs, and control of 2D size and spacing of the spherical void pattern. Electrochemical-quartz crystal microbalance (EC-QCM) in situ monitoring of the film deposition quantified a constant and linear growth rate, with varying viscoelastic behavior of the conducting polymer adsorption on planar and PS-templated substrates. The dual-patterned surface provided a good imaging contrast as observed by atomic force microscopy (AFM). Complementary analyses such as X-ray photoelectron spectroscopy (XPS), attenuated total internal reflection infrared (ATR IR) spectroscopy, ultraviolet-visible (UV-vis) spectroscopy, and static contact angle measurements were used to characterize the formation of the patterned surface. The versatility of the method enables the potential for making various types of quantitative binary compositions and patterned surfaces using different combinations of conducting polymer or functional SAMs, which can be extended in the future to polymer brushes and layer-by-layer assembly of various materials.

Functionalized Polymers as Receptors for Detection of Cells

Mass sensitive sensors were applied for fast and label-free detection of bio-analytes. Robust and miniaturized sensor devices were fabricated by combining bio-mimetic imprinted surfaces with quartz crystal microbalances for the analysis of yeast and bacteria cells. These sensors allow us to differentiate between different growing stages of yeast cells. Moreover, the viability of cells was detected by structuring quartz crystal microbalance electrodes like a grid. Artificial yeast cells were produced to pattern the recognition layer, giving reversible enrichment of the respective bio-analytes. This approach was followed to ensure the reproducibility of the identical sensitive material in each case, because the properties of each cell depend on its growth stage, which varies over time. The strategy was further applied to develop a sensitive system for Escherichia coli. Structuring of these materials by soft lithography allows differentiation between cell strains, e.g. E. coli (strain W & B) with a five-fold selectivity.