Giant stretchability of thin gold films on rough elastomeric substrates

Stretching metallic conductors to large deformations while maintaining a low and constant electrical resistance is one of the main challenges in stretchable electronics technologies. Here, we report the conservation of conductivity for deformations of up to 100% in 80 and 500 nm thick gold films deposited on rough polydimethylsiloxane (PDMS) substrates. The roughness is produced by curing PDMS on sand-blasted or surface-etched masters. Under stretching, roughness creates a fine-scale inhomogeneous stress state within the film and a non-percolating crack pattern develops, preserving the conductivity. Compared to smooth surfaces, the strain corresponding to electrical failure is increased by a factor >50. By combining the roughness effect with prestretching of the substrate during deposition, a fine-scale random wrinkling morphology develops and the stretchability is enhanced even further. The stretchability is finally improved by increasing the thickness of the film. These synergistic effects can be explained based on fracture mechanics arguments. Finally, a high number of large deformation cycles can be accommodated without electrical failure. © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved

Mirror

The invention relates to a mirror including a glass substrate covered with a silver layer, which is in turn covered with at least one paint layer, wherein the intensity ratio of the crystallographic orientations (111)/(200) within the silver layer is less than 5.0. Said mirror is characterized in that the silver layer has a correlation length (CLz) (111), as measured by X-ray diffraction using the Scherrer method (i.e., using the Scherrer equation) of greater than 27.0 nm

Coadministration of a Plasmid Encoding HIV-1 Gag Enhances the Efficacy of Cancer DNA Vaccines.

DNA vaccination holds great promise for the prevention and treatment of cancer and infectious diseases. However, the clinical ability of DNA vaccines is still controversial due to the limited immune response initially observed in humans. We hypothesized that electroporation of a plasmid encoding the HIV-1 Gag viral capsid protein would enhance cancer DNA vaccine potency. DNA electroporation used to deliver plasmids in vivo, induced type I interferons, thereby supporting the activation of innate immunity. The coadministration of ovalbumin (OVA) and HIV-1 Gag encoding plasmids modulated the adaptive immune response. This strategy favored antigen-specific Th1 immunity, delayed B16F10-OVA tumor growth and improved mouse survival in both prophylactic and therapeutic vaccination approaches. Similarly, a prophylactic DNA immunization against the melanoma-associated antigen gp100 was enhanced by the codelivery of the HIV-1 Gag plasmid. The adjuvant effect was not driven by the formation of HIV-1 Gag virus-like particles. This work highlights the ability of both electroporation and the HIV-1 Gag plasmid to stimulate innate immunity for enhancing cancer DNA vaccine immunogenicity and demonstrates interesting tracks for the design of new translational genetic adjuvants to overcome the current limitations of DNA vaccines in humans

Biomimetic hydrogel-CNT network induced enhancement of fluid-structure interactions for ultrasensitive nanosensors

Flexible, self-powered, miniaturized, ultrasensitive flow sensors are in high demand for human motion detection, myoelectric prosthesis, biomedical robots, and health-monitoring devices. This paper reports a biomimetic nanoelectromechanical system (NEMS) flow sensor featuring a PVDF nanofiber sensing membrane with a hydrogel infused, vertically aligned carbon nanotube (VACNT) bundle that mechanically interacts with the flow. The hydrogel-VACNT structure mimics the cupula structure in biological flow sensors and gives the NEMS flow sensor ultrahigh sensitivity via a material-induced drag force enhancement mechanism. Through hydrodynamic experimental flow characterization, this work investigates the contributions of the mechanical and structural properties of the hydrogel in offering a sensing performance superior to that of conventional sensors. The ultrahigh sensitivity of the developed sensor enabled the detection of minute flows generated during human motion and micro-droplet propagation. The novel fabrication strategies and combination of materials used in the biomimetic NEMS sensor fabrication may guide the development of several wearable, flexible, and self-powered nanosensors in the future.NRF (Natl Research Foundation, S’pore)Published versio