Oxidation of the reductants is a dominant factor in the electroless deposition process. In order to obtain fundamental knowledge about the reaction mechanism of reductant oxidation for more precise control of the solid-liquid interface in this process, we have attempted to characterize the behavior of reductants adsorbed on Cu surface by using plasmon antenna enhanced Raman scattering. The concentric-patterned antenna coated with Cu, which consisted of a dimple array with single hole or a single hole with coaxial dimples, was designed by Finite Difference Time Domain (FDTD) calculation to enhance the electric field by focusing surface plasmons. By using this antenna and comparing the spectra to the results of Density Functional Theory (DFT) calculations, Raman peaks of adsorbed reductants on Cu were identified. Furthermore, we examined the conformation of adsorbed reductants by DFT calculation of the adsorption model of reductants on fcc-Cu(111) surface. As a result, the nature of reductant adsorption on Cu surface has been investigated from a computational point of view and an experimental point of view, and such in-situ characterization will be useful for analysis of a variety of systems at solid-liquid interface.
An electroless NiP imprinting mold was fabricated through replication of a cyclo-olefin polymer (COP) master mold. The NiP was electrolessly deposited on a nanopatterned COP master mold, pretreated by ultraviolet (UV) irradiation prior to modification with 3-aminopropyltriethoxysilane (APTES). The NiP deposit as a “replicate” was then detached from the COP master mold. Additionally, by optimizing the UV irradiation period, APTES could be formed on the COP master mold for electroless deposition without disturbing the nanopattern geometry of the COP master mold. The water contact angle and surface morphology of the COP surface, and the adhesion strength between deposited NiP and the COP surface were investigated.
A local redox cycling-based electrochemical (LRC-EC) chip device was used to investigate the relationship between cardiomyocyte differentiation from embryonic stem (ES) cells and alkaline phosphatase (ALP) activity. In the LRC-EC chip device, ring-type interdigitated array electrodes were incorporated at n × n measurement points with only 2n bonding pads for external connection. Microwells were also fabricated at each measurement point to trap cell aggregates. To differentiate ES cells into cardiomyocytes, ES cells were three-dimensionally cultured to form simple and cystic embryoid bodies (EBs). ALP activity of these EBs was then detected using the LRC-EC chip device. The electrochemical responses for ALP activity decreased concurrently with the differentiation of ES cells into cardiomyocytes, indicating that an LRC-EC chip device is useful for evaluating cell differentiation.
The sweep rate for cyclic voltammetry has been shown to be unequivocally the ratio of the incremental potential ΔE to the number of iterations during the potential change Nstep within the framework of one-dimensional electrochemical cellular automaton. Unifying the diffusion and the electron transfer fixes the magnitude of time step δt that corresponds to one iterative cycle. Depending on the rate of electron transfer, the values of δt may range from microseconds to milliseconds for ordinary values of the diffusion coefficient.