Nanostructured Molecular Packing of Polymer Films Formed on Water Surfaces.

In this study, we examined the nanostructured molecular packing and orientations of poly[[N,N'-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5'-(2,2'-bithiophene)] (P(NDI2OD-T2)) films formed on water for the application of nanotechnology-based organic electronic devices. First, the nanoscale molecule-substrate interaction between the polymer and water was modulated by controlling the alkyl side chain length in NDI-based copolymers. Increasing alkyl side chain lengths induced a nanomorphological transition from face-on to edge-on orientation, confirmed by molecular dynamics simulations revealing nanostructural behavior. Second, the nanoscale intermolecular interactions of P(NDI2OD-T2) were controlled by varying the volume ratio of the high-boiling-point additive solvent in the binary solvent blends. As the additive solvent ratio increased, the nanostructured molecular orientation of the P(NDI2OD-T2) films on water changed remarkably from edge-on to bimodal with more face-on crystallites, thereby affecting charge transport. Our finding provides essential insights for precise nanoscale morphological control on water substrates, enabling the formation of high-performance polymer films for organic electronic devices.

Flexible Bottom-Gated Organic Field-Effect Transistors Utilizing Stamped Polymer Layers from the Surface of Water.

The facile sequential deposition of functional organic thin films by solution processes is critical for the development of a variety of high-performance organic devices without restriction in terms of materials and processes. Herein, we propose a simple fabrication process that entails stacking multiple layers of functional polymers to fabricate organic field-effect transistors (OFETs). The process involves stamping organic semiconducting layers formed on the surface of water onto a commonly used polymeric dielectric layer. Our scheme makes it possible to independently optimize organic semiconductor films by controlling the solvent evaporation time during the process of film formation on the surface of water. This approach eliminates the need to be concerned about any interference with adjacent layers. Utilizing this process, the fabrication of high-performance bottom-gated OFETs is demonstrated on a glass and a flexible substrate. The OFETs consist of a vertically stacked diketopyrrolopyrrole-based polymer semiconducting layer on the poly(methyl methacrylate) film with a maximum hole mobility of 0.85 cm2/V s.

Development of Au nanowire injector system to deliver plasmid into mouse embryo.

In this data article, we developed a Au nanowire injector (Au NWI) for directly delivering plasmid into the 1-cell stage of the mouse embryos designed to successfully attach and detach the plasmid on the Au NWI, highly minimizing physical and chemical damage on the embryos. This data presents that a Au NWI system does not induce detrimental damages on development of embryos and efficiently express the green fluorescence protein in vitro. The data provided herein is in association with the research article related to reduce the occurrence of mosaicism by a Au NWI," Suppressing Mosaicism by Au Nanowire Injector-driven Direct Delivery of Plasmids into Mouse Embryos" (Park et al., 2017 [1]).

Suppressing mosaicism by Au nanowire injector-driven direct delivery of plasmids into mouse embryos.

Transgenic animals have become key tools in a variety of biomedical research areas. However, microinjection commonly used for producing transgenic animals has several challenges such as physical and chemical damage to the embryos due to microinjector with buffer, and low transgene integration rates with frequent mosaicism. Here, we report direct delivery of plasmids into mouse embryos using a Au nanowire injector (NWI) that significantly improved transgene integration efficiency and suppressed mosaicism. The Au NWI could deliver plasmid into the pronucleus (PN) of a mouse zygote without buffer and rapidly release it with electric pulse. Because zygote, which is a fertilized 1-cell stage embryo, has two physical barriers (cytoplasmic membrane and zona pellucida), direct delivery of plasmids into PN of zygote is more difficult than into a normal cell type. To penetrate the two physical barriers with minimal disruption of the embryo, we optimized the diameter and length of Au NWI. The mosaicism is more reduced in the Au NWI injected embryos than in micropipette injected embryos, which was determined by the expression of transgene in a blastocyst stage. We suggest that Au NWI can increase the efficiency of gene delivery into zygote with suppressed mosaicism and become a useful alternative.