Obesity is important for the development of type-2 diabetes as a result of obesity-induced insulin resistance accompanied by impaired compensation of insulin secretion from pancreatic beta cells. Here, based on a randomized pilot clinical trial, we report that intranasal oxytocin administration over an 8-week period led to effective reduction of obesity and reversal of related prediabetic changes in patients. Using mouse models, we further systematically evaluated whether oxytocin and its analogs yield therapeutic effects against prediabetic or diabetic disorders regardless of obesity. Our results showed that oxytocin and two analogs including [Ser4, Ile8]-oxytocin or [Asu1,6]-oxytocin worked in mice to reverse insulin resistance and glucose intolerance prior to reduction of obesity. In parallel, using streptozotocin-induced diabetic mouse model, we found that treatment with oxytocin or its analogs reduced the magnitude of glucose intolerance through improving insulin secretion. The anti-diabetic effects of oxytocin and its analogs in these animal models can be produced similarly whether central or peripheral administration was used. In conclusion, oxytocin and its analogs have multi-level effects in improving weight control, insulin sensitivity and insulin secretion, and bear potentials for being developed as therapeutic peptides for obesity and diabetes.

Silicon nanowires/TiO (SiNWs/TiO) array with core-shell nanostructure was created by sol-gel and drop-casting methods. The hybrid material displayed excellent sensing performance for CH detection at room temperature. The chemiresistor sensor has a linear response toward CH gas in the 30-120 ppm range with a detection limit of 20 ppm, which is well below most CH sensors reported before. The enhanced gas sensing performance at room temperature was attributed to the creation of heterojunctions that form a depletion layer at the interface of SiNWs and TiO layer. Adsorption of oxygen and corresponding gas analyte on TiO layer could induce the change of depletion layer thickness and consequently the width of the SiNWs conductive channel, leading to a sensitive conductive response toward gas analyte. Compared to conventional metal oxide gas sensors, the room temperature gas sensors constructed from SiNWs/TiO do not need an additional heating device and work at power at the μW level. The low power consumption feature is of great importance for sensing devices, if they are widely deployed and connected to the Internet of Things. The innovation of room temperature sensing materials may push forward the integration of gas sensing element with wireless device.

A flexible electronic-nose (E-nose) was constructed by assembling graphene oxide (GO) using different types of metal ions (M x+) with different ratio of GO to M x+. Owing to the cross-linked networks, the M x+-induced assembly of graphene films resulted in different porous structures. A chemi-resistive sensor array was constructed by coating the GO–M hybrid films on PET substrate patterned with 8 interdigited electrodes, followed by in situ reduction of GO to rGO with hydrazine vapor. Each of the sensing elements on the sensor array showed a cross-reactive response toward different types of gases at room temperature. Compared to bare rGO, incorporation of metal species into rGO significantly improved sensitivity owing to the additional interaction between metal species and gas analyte. Principle component analysis (PCA) showed that four types of exhaled breath (EB) biomarkers including acetone, isoprene, ammonia, and hydrothion in sub-ppm concentrations can be discriminated well. To overcome the interference from humidity in EB, a protocol to collect and analyze EB gases was established and further validated by simulated EB samples. Finally, clinical EB samples collected from patients with lung cancer and healthy controls were analyzed. In a 106 case study, the healthy group can be accurately distinguished from lung cancer patients by linear discrimination analysis. With the assistance of an artificial neural network, a sensitivity of 95.8% and specificity of 96.0% can be achieved in the diagnosis of lung cancer based on the E-nose. We also find that patients with renal failure can be distinguished through comparison of dynamic response curves between patient and healthy samples on some specific sensing elements. These results demonstrate the proposed E-nose will have great potential in noninvasive disease screening and personalized healthcare management.

In order to distinguish NO and SO gas with one sensor, we designed a paper chip assembled with a 2D g-CN/rGO stacking hybrid fabricated via a layer-by-layer self-assembly approach. The g-CN/rGO hybrid exhibited a remarkable photoelectric property due to the construction of a van der Waals heterostructure. For the first time, we have been able to selectively detect NO and SO gas using a "light on and off" strategy. Under the "light off" condition, the g-CN/rGO sensor exhibited a p-type semiconducting behavior with a low detection limit of 100 ppb of NO, but with no response toward SO. In contrast, the sensor showed n-type semiconducting behavior which could detect SO at concentration as low as 2 ppm under UV light irradiation. The effective electron transfer among the 2D structure of g-CN and rGO nanosheets as well as highly porous structures could play an important role in gas sensing. The different sensing mechanisms at "light on and off" circumstances were also investigated in detail.

No abstract