Mesenchymal stem cells (MSCs) have been considered as an attractive tool for the therapy of diseases. Exosomes excreted from MSCs can reduce myocardial ischemia/reperfusion damage and protect against acute tubular injury. However, whether MSC-derived exosomes can relieve liver fibrosis and its mechanism remain unknown. Previous work showed that human umbilical cord-MSCs (hucMSCs) transplanted into acutely injured and fibrotic livers could restore liver function and improve liver fibrosis. In this study, it was found that transplantation of exosomes derived from hucMSC (hucMSC-Ex) reduced the surface fibrous capsules and got their textures soft, alleviated hepatic inflammation and collagen deposition in carbon tetrachloride (CCl 4 )-induced fibrotic liver. hucMSC-Ex also significantly recovered serum aspartate aminotransferase (AST) activity, decreased collagen type I and III, transforming growth factor (TGF)-b1 and phosphorylation Smad2 expression in vivo. In further experiments, we found that epithelial-to-mesenchymal transition (EMT)-associated markers E-cadherin-positive cells increased and N-cadherin-and vimentin-positive cells decreased after hucMSC-Ex transplantation. Furthermore, the human liver cell line HL7702 underwent typical EMT after induction with recombinant human TGF-b1, and then hucMSC-Ex treatment reversed spindle-shaped and EMT-associated markers expression in vitro. Taken together, these results suggest that hucMSC-Ex could ameliorate CCl 4 -induced liver fibrosis by inhibiting EMT and protecting hepatocytes. This provides a novel approach for the treatment of fibrotic liver disease.

In this work, we have reported a vertical CsPbBr3/ZnO heterojunction photodetector for photo-sensing lights from UV to visible band. The ZnO thin film is deposited on the c-sapphire substrate through a molecular beam epitaxy (MBE) technique, and then the CsPbBr3 thin film is synthesized on the as-prepared ZnO film layer by using a solution processing method. The as-prepared CsPbBr3/ZnO heterostructure presents type-II energy band structure induced by the energy band offset effect, which can promote the separation and extraction efficiencies of the photo-generated electron-hole pairs. Compared with the CsPbBr3 based metal-semiconductor-metal (MSM) structure photodetector, the heterojunction photodetector presents higher responsivity and detectivity of 630 µA/W and 7 × 109 Jones. While compared with the ZnO based MSM structure photodetector, the heterojunction device reveals much faster response speeds of 61 µs (rise time) and 1.4 ms (decay time). These findings demonstrate that the CsPbBr3/ZnO heterojunction photodetector is promising for constructing next generation perovskite based optoelectronic devices.

An ultra-sensitive fiber optic sensor based on a H O ( M e 2 S i O ) n H (silicone rubber) Fabry–Pérot (FP) resonant cavity is fabricated through a simple method of dipping, which has high linearity, high sensitivity, and a wide response range to temperature. The silicone rubber can form a smooth sphere without wire drawing, and it has strong heat resistance and aging resistance. Its favorable waterproof performance enables it to work efficiently in different humid environments. A method of synchronizing the detection and wavelength sweeping signal is applied to analyze the wavelength shifts of the interference signal. The sensitivity of the fabricated FP sensor is almost 400 pm/°C in the range of 50–190°C with a linearity of 0.999, and the resolution is 0.002 nm. In addition, the testing results at room temperature can also satisfy the linear relationship, providing the possibility of applications in the biological field.