Highly Conductive Flexible Metal-Ceramic Nanolaminate Electrode for High-Performance Soft Electronics.

Realization of flexible electronics is an attractive challenge because of its great potential in many applications. However, the design of flexible and highly conductive metal electrodes has been a bottleneck for the fabrication of flexible devices because bulk metals are easily fractured when subjected to elongation or compression. Here, we demonstrate metal-ceramic nanolaminates as electrodes for flexible electronic devices. Insertion of ceramic layers, each with a thickness of a few nanometers, into an otherwise metal electrode significantly improved its strength and bending stability and only slightly reduced its electrical conductivity. Finally, we demonstrated that a touch screen panel fabricated with metal-ceramic nanolaminate electrodes was stable to 200 000 cycles of folding to a bending radius of 3 mm.

Flexible Near-Field Wireless Optoelectronics as Subdermal Implants for Broad Applications in Optogenetics.

In vivo optogenetics provides unique, powerful capabilities in the dissection of neural circuits implicated in neuropsychiatric disorders. Conventional hardware for such studies, however, physically tethers the experimental animal to an external light source, limiting the range of possible experiments. Emerging wireless options offer important capabilities that avoid some of these limitations, but the current size, bulk, weight, and wireless area of coverage is often disadvantageous. Here, we present a simple but powerful setup based on wireless, near-field power transfer and miniaturized, thin, flexible optoelectronic implants, for complete optical control in a variety of behavioral paradigms. The devices combine subdermal magnetic coil antennas connected to microscale, injectable light-emitting diodes (LEDs), with the ability to operate at wavelengths ranging from UV to blue, green-yellow, and red. An external loop antenna allows robust, straightforward application in a multitude of behavioral apparatuses. The result is a readily mass-producible, user-friendly technology with broad potential for optogenetics applications.

Long-term visual outcome and prognostic factors of Intravitreal anti-vascular endothelial growth factor treatment for retinal angiomatous proliferation.

PURPOSE: To evaluate the long-term visual outcomes and investigate the prognostic factors of anti-vascular endothelial growth factor (VEGF) therapy for retinal angiomatous proliferation (RAP). METHODS: Thirty-eight treatment-naïve RAP eyes (38 patients) that received intravitreal anti-VEGF (ranibizumab and/or bevacizumab) injections were included and analyzed in this retrospective case series. All patients were treated with an initial series of three monthly intravitreal anti-VEGF injections, followed by as-needed injections for a total of 36 months. RESULTS: The mean number of anti-VEGF injections was 9.61 ± 3.1 during the 36-month follow-up. Mean baseline best-corrected visual acuity (BCVA) was 0.79 ± 0.56 logarithm of the minimum angle of resolution (logMAR; 20/123 Snellen equivalent), and 0.75 ± 0.41 logMAR (20/112 Snellen equivalent) at 36 months (P = 0.55). Mean BCVA significantly improved at 3 months (P = 0.001), and the significant improvement persisted until 18 months from baseline (P = 0.02). However, the mean BCVA between 18 and 36 months showed no statistical in comparison with baseline values. Geographic atrophy developed in 14 eyes (36.8 %) during the entire 36-month follow-up period. Among baseline characteristics, baseline BCVA, greatest lesion diameter (GLD), and lesion size were significantly correlated with long-term visual outcome (P = 0.008, 0.02, and 0.002 respectively). CONCLUSIONS: Intravitreal anti-VEGF injections for RAP showed a favorable visual outcome during the first year; however, the visual gains declined after the second year from baseline. Better baseline BCVA, smaller lesion size, and smaller baseline GLD are associated with better long-term visual outcomes in patients with RAP.

Abnormal behavior of threshold voltage shift in bias-stressed a-Si:H thin film transistor under extremely high intensity illumination.

We report on the unusual behavior of threshold voltage turnaround in a hydrogenated amorphous silicon (a-Si:H) thin film transistor (TFT) when biased under extremely high intensity illumination. The threshold voltage shift changes from negative to positive gate bias direction after ∼30 min of bias stress even when the negative gate bias stress is applied under high intensity illumination (>400 000 Cd/cm(2)), which has not been observed in low intensity (∼6000 Cd/cm(2)). This behavior is more pronounced in a low work function gate metal structure (Al: 4.1-4.3 eV), compared to the high work function of Cu (4.5-5.1 eV). Also this is mainly observed in shorter wavelength of high photon energy illumination. However, this behavior is effectively prohibited by embedding the high energy band gap (∼8.6 eV) of SiOx in the gate insulator layer. These imply that this behavior could be originated from the injection of electrons from gate electrode, transported and trapped in the electron trap sites of the SiNx/a-Si:H interface, which causes the shift of threshold voltage toward positive gate bias direction. The results reported here can be applicable to the large-sized outdoor displays which are usually exposed to the extremely high intensity illumination.

Water-soluble thin film transistors and circuits based on amorphous indium-gallium-zinc oxide.

This paper presents device designs, circuit demonstrations, and dissolution kinetics for amorphous indium-gallium-zinc oxide (a-IGZO) thin film transistors (TFTs) comprised completely of water-soluble materials, including SiNx, SiOx, molybdenum, and poly(vinyl alcohol) (PVA). Collections of these types of physically transient a-IGZO TFTs and 5-stage ring oscillators (ROs), constructed with them, show field effect mobilities (∼10 cm2/Vs), on/off ratios (∼2×10(6)), subthreshold slopes (∼220 mV/dec), Ohmic contact properties, and oscillation frequency of 5.67 kHz at supply voltages of 19 V, all comparable to otherwise similar devices constructed in conventional ways with standard, nontransient materials. Studies of dissolution kinetics for a-IGZO films in deionized water, bovine serum, and phosphate buffer saline solution provide data of relevance for the potential use of these materials and this technology in temporary biomedical implants.

Soft network composite materials with deterministic and bio-inspired designs.

Hard and soft structural composites found in biology provide inspiration for the design of advanced synthetic materials. Many examples of bio-inspired hard materials can be found in the literature; far less attention has been devoted to soft systems. Here we introduce deterministic routes to low-modulus thin film materials with stress/strain responses that can be tailored precisely to match the non-linear properties of biological tissues, with application opportunities that range from soft biomedical devices to constructs for tissue engineering. The approach combines a low-modulus matrix with an open, stretchable network as a structural reinforcement that can yield classes of composites with a wide range of desired mechanical responses, including anisotropic, spatially heterogeneous, hierarchical and self-similar designs. Demonstrative application examples in thin, skin-mounted electrophysiological sensors with mechanics precisely matched to the human epidermis and in soft, hydrogel-based vehicles for triggered drug release suggest their broad potential uses in biomedical devices.

Rugged and breathable forms of stretchable electronics with adherent composite substrates for transcutaneous monitoring.

Research in stretchable electronics involves fundamental scientific topics relevant to applications with importance in human healthcare. Despite significant progress in active components, routes to mechanically robust construction are lacking. Here, we introduce materials and composite designs for thin, breathable, soft electronics that can adhere strongly to the skin, with the ability to be applied and removed hundreds of times without damaging the devices or the skin, even in regions with substantial topography and coverage of hair. The approach combines thin, ultralow modulus, cellular silicone materials with elastic, strain-limiting fabrics, to yield a compliant but rugged platform for stretchable electronics. Theoretical and experimental studies highlight the mechanics of adhesion and elastic deformation. Demonstrations include cutaneous optical, electrical and radio frequency sensors for measuring hydration state, electrophysiological activity, pulse and cerebral oximetry. Multipoint monitoring of a subject in an advanced driving simulator provides a practical example.

Acute retinal pigment epitheliitis: spectral-domain optical coherence tomography findings in 18 cases.

PURPOSE: To describe the imaging characteristics and to investigate the prognostic factors of acute retinal pigment epitheliitis. METHODS: In this retrospective observational case series, a total of 18 patients (18 eyes) with acute retinal pigment epitheliitis were included. The features of acute retinal pigment epitheliitis were analyzed by spectral-domain optical coherence tomography (SD-OCT). RESULTS: Spectral domain-OCT images obtained at baseline revealed abnormal reflectivity in the RPE inner layer in every case (18 eyes, 100%). The line corresponding to the RPE inner layer, the inner segment ellipsoid (ISe), showed abnormal reflectivity in 16 cases (89%). Among patients with ISe abnormalities, three eyes (17%) also showed external limiting membrane (ELM) disruption and two expanded abnormal reflectivity in the outer nuclear layer (ONL). With time, SD-OCT images showed disappearance and gradual resolution of the ONL hyperreflectivity, and disruption of the ELM or ISe. Sixteen eyes (89%) fully recovered their BCVA within 2 months. However, two eyes (11%) with involvement of the ELM or ONL at baseline, with BCVA of less than 20/70 at baseline, showed incomplete BCVA recovery after more than 1 year of follow-up. CONCLUSIONS: Spectral domain-OCT findings indicated that the initial lesion in acute retinal pigment epitheliitis is located at the junction between the photoreceptor outer segments and the apical sides of the RPE cells. Poor visual acuity at baseline and involvement of the ELM or ONL on SD-OCT at baseline were associated with the incomplete recovery of visual acuity.

Glaucoma in an eye with situs inversus of the optic disc.

Situs inversus of the optic disc is a congenital abnormality characterized by dysversion of the optic nerve head and surrounding retinal vessels. Here, we report the retinal nerve fiber layer (RNFL) characteristics of eyes with situs inversus of the optic discs with and without glaucoma, as imaged using spectral-domain optical coherence tomography (OCT). OCT findings of an eye with situs inversus of optic disc and uveitic glaucoma revealed abnormal RNFL thinning. After six months of treatment, progressive RNFL thinning in the superior-nasal and inferior-nasal areas was found. The fellow eye with situs inversus of the optic disc without glaucoma showed a thicker nasal RNFL, a thinner temporal RNFL, and more nasally located RNFL peak locations compared with normative database. RNFL thickness characteristics in eyes with situs inversus of the optic discs, presented here, should be considered when assessing glaucoma in eyes with this abnormality.