Electrically conductive cotton fabric coatings developed by silica sol-gel precursors doped with surfactant-aided dispersion of vertically aligned carbon nanotubes fillers in organic solvent-free aqueous solution.

HYPOTHESIS: From the end of the twentieth century, the growing interest in a new generation of wearable electronics with attractive application for military, medical and smart textiles fields has led to a wide investigation of chemical finishes for the production of electronic textiles (e-textiles). EXPERIMENTS: Herein, a novel method to turn insulating cotton fabrics in electrically conductive by the deposition of three-dimensional hierarchical vertically aligned carbon nanotubes (VACNT) is proposed. Two VACNT samples with different length were synthesized and then dispersed in 4-dodecylbenzenesulfonic acid combined with silica-based sol-gel precursors. The dispersed VACNT were separately compounded with a polyurethane thickener to obtain homogeneous spreadable pastes, finally coated onto cotton surfaces by the "knife-over-roll" technique. FINDINGS: Shorter VACNT-based composite showed the best electrical conductivity, with a sheet resistance value less than 4.0 · 104 ± 6.7 · 103 Ω/sq. As demonstrated, developed e-textiles are suitable for application as humidity sensing materials in wearable smart textiles by exhibiting adequate response time for end-users and repeatability at several exposure cycles, still maintaining excellent flexibility. The proposed environmentally-friendly and cost-effective method can be easily widened to the scalable production of CNT-containing conductive flexible coatings, providing additional support to the development of real integration between electronics and textiles.

Carbon nanostructures as a scaffold for human embryonic stem cell differentiation toward photoreceptor precursors.

Carbon nanomaterials have been introduced as a scaffold for various biological applications due to their unique physical and electrical properties. Here we studied carbon nanotubes (CNTs) and carbon nanofibers (CNFs) as scaffold materials for the differentiation of human embryonic stem cells (hESCs) towards photoreceptor precursor cells (PRPs). We report on their cytoxicity, their effect on cell morphology, cell-surface interface and the differentiation process. To this end, hESCs were differentiated into PRPs on carbon nanofibers (CNFs), long horizontal CNTs (LHCNTs), vertically aligned CNTs (VACNTs) or glass (control) surfaces. The differentiated cells were investigated by immunohistochemistry, fluorescence imaging and electron microscopy. Our results revealed that the investigated nanomaterials were not cytotoxic to the cells during the differentiation process. The surface interface effect on the cells was apparent, affecting cell directionality, migration and morphology. Interestingly, cell fate was not dependent on the substrate type, as inferred from the similar dynamics of the loss of pluripotency and the comparable expression levels of the photoreceptor marker Crx for all investigated substrates. These results are important for better understanding the effect of nanomaterial surface interaction with differentiating neural cells in general, and for future use of these materials as scaffolds for differentiating photoreceptors for vision restoration in particular.