Ken Nakajima

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Dielectrophoresis is used to align carbon nanotubes (CNTs) within gelatin methacrylate (GelMA) hydrogels in a facile and rapid manner. Aligned GelMA-CNT hydrogels show higher electrical properties compared with pristine and randomly distributed CNTs in GelMA hydrogels. The muscle cells cultured on these materials demonstrate higher maturation compared with(More)
Engineering functional muscle tissue requires the formation of densely packed, aligned, and mature myotubes. To enhance the formation of aligned myotubes with improved contractibility, we fabricated aligned electrospun gelatin multi-walled carbon nanotubes (MWNTs) hybrid fibers that were used as scaffolds for the growth of myoblasts (C2C12). The MWNTs(More)
Controlling the cellular microenvironment can be used to direct the cellular organization, thereby improving the function of synthetic tissues in biosensing, biorobotics, and regenerative medicine. In this study, we were inspired by the microstructure and biological properties of the extracellular matrix to develop freestanding ultrathin polymeric films(More)
Engineered surface-bound molecular gradients are of great importance for a range of biological applications. In this paper, we fabricated a polydopamine gradient on a hydrophobic surface. A microfluidic device was used to generate a covalently conjugated gradient of polydopamine (PDA), which changed the wettabilty and the surface energy of the substrate.(More)
Graphene was embedded into the structure of mouse embryoid bodies (EBs) using the hanging drop technique. The inclusion of 0.2 mg per mL graphene in the EBs did not affect the viability of the stem cells. However, the graphene decreased the stem cell proliferation, probably by accelerating cell differentiation. The graphene also enhanced the mechanical(More)
Biological scaffolds with tunable electrical and mechanical properties are of great interest in many different fields, such as regenerative medicine, biorobotics, and biosensing. In this study, dielectrophoresis (DEP) was used to vertically align carbon nanotubes (CNTs) within methacrylated gelatin (GelMA) hydrogels in a robust, simple, and rapid manner.(More)
We proposed a facile, low cost, and green approach to produce stable aqueous graphene dispersions from graphite by sonication in aqueous bovine serum albumin (BSA) solution for biomedical applications. The production of high-quality graphene was confirmed using microscopy images, Raman spectroscopy, UV-vis spectroscopy, and XPS. In addition, ab initio(More)
Direct imaging of the bulk heterojunction (BHJ) thin film morphology in polymer-based solar cells is essential to understand device function and optimize efficiency. The morphology of the BHJ active layer consists of bicontinuous domains of the donor and acceptor materials, having characteristic length scales of several tens of nanometers, that reduces(More)
The controlled assembly of protein domains into supramolecular structures will be an important prerequisite for the use of functional proteins in future nanotechnology applications. Coiled coils are multimerization motifs whose dimerization properties can be programmed by amino acid sequence. Here, we report programmed supramolecular self-assembly of(More)