Multifunctional acetylated distarch phosphate based conducting hydrogel with high stretchability, ultralow hysteresis and fast response for wearable strain sensors.

The rapid development of flexible sensors has greatly increased the demand for high-performance hydrogels. However, it remains a challenge to fabricate flexible hydrogel sensors with high stretching, low hysteresis, excellent adhesion, good conductivity, sensing characteristics and bacteriostatic function in a simple way. Herein, a highly conducting double network hydrogel is presented by incorporating lithium chloride (LiCl) into the hydrogel consisting of poly (2-acrylamide-2-methylpropanesulfonic acid/acrylamide/acrylic acid) (3A) network and acetylated distarch phosphate (ADSP). The addition of ADSP not only formed hydrogen bonds with 3A to improve the toughness of the hydrogel but also plays the role of "physical cross-linking" in 3A by "anchoring" the polymer molecular chains together. Tuning the composition of the hydrogel allows the attainment of the best functions, such as high stretchability (∼770 %), ultralow hysteresis (2.2 %, ε = 100 %), excellent electrical conductivity (2.9 S/m), strain sensitivity (GF = 3.0 at 200-500 % strain) and fast response (96 ms). Based on the above performance, the 3A/ADSP/LiCl hydrogel strain sensor can repeatedly and stably detect and monitor large-scale human movements and subtle sensing signals. In addition, the 3A/ADSP/LiCl hydrogel shows a good biocompatibility and bacteriostatic ability. This work provides an effective strategy for constructing the conductive hydrogels for wearable devices and flexible sensors.

Self-complementary hydrogen-bond interactions of guanosine: a hub for constructing supra-amphiphilic polymers with controlled molecular structure and aggregate morphology.

A supra-amphiphilic polymer (SAP) with controlled molecular structures is constructed, in this work, via self-complementary hydrogen bonding of guanosine groups between a hydrophilic block, poly(N-isopropylacrylamide), and a hydrophobic block, poly(ε-caprolactone). By simply changing the mixing ratio of the guanosine-capped hydrophilic and hydrophobic blocks, a series of SAPs with tailored nanostructures are constructed, which can further self-assemble into different nano-aggregates in solution, including spheres, vesicles and large vesicle micelles. The thermo-induced phase transition of the hydrophilic block induces the fusion and aggregation of the nanoparticles into irregular particles upon heating, which further transform to large compound vesicles after cooling.

Strategy for Constructing Shape-Memory Dynamic Networks through Charge-Transfer Interactions.

Recently, charge transfer (CT) interactions have received attention for the fabrication of supramolecular architectures due to their inherent compatibilities, directional nature and solvent tolerance. In this study, we report a shape-memory dynamic network constructed by the CT interaction between π-electron-rich naphthalene embedded in poly(ethylene glycol) (PEG-Np) and π-electron-poor six-arm methyl-viologen-ended poly(ethylene glycol) (6PEG-MV), which was verified by ultraviolet-visible spectroscopy (UV-vis), fluorescence spectra and swelling tests. Interestingly, the mechanical properties of this CT complex were dramatically enhanced compared with the control without CT interaction. Moreover, the excellent shape-memory effect (SME) was realized due to the good crystallization of the PEG segment and stable netpoints based on the CT interaction. In addition, as we expected, this supramolecular polymer network is self-healable and reprocessable.

Electrostatic wrapping of doxorubicin with curdlan to construct an efficient pH-responsive drug delivery system.

The development of environmentally responsive drug delivery systems for the treatment of cancer has attracted particular interest in recent years. However, the enhancement of drug loading capacity and realization of pH-responsive drug delivery remain challenging. Herein, we employ carboxymethyl curdlan as a hydrophilic carrier to wrap doxorubicin (DOX) directly via electrostatic interaction. The sizes of the formed nanoparticles can be simply tuned by changing their feeding ratios. In particular, the nanoparticles are highly stable in aqueous solution without size variation. In vitro drug release and cytotoxicity assays illustrate that this delivery system can release DOX differentially under various environmental conditions and transport it into cell nuclei efficiently, with comparable therapeutic effect to the free drug. These results suggest that the carrying of antitumor drugs by polysaccharide via electrostatic interaction is a simple but effective way to construct a pH-dependent drug delivery platform.

[Analysis of qualifications of medical and health institutions and certified doctors for providing occupational disease diagnosis in China].

OBJECTIVE: To investigate the qualifications and current situations of the medical and health institutions and certified doctors for providing occupational disease diagnosis in China and to provide a reference for developing relevant policies. METHODS: Work reports and questionnaires survey were used to investigate the qualifications of all medical and health institutions and certified doctors for providing occupational disease diagnosis in China and their acceptance and diagnosis of occupational disease cases from 2006 to 2010. The rate for the work reports was 100%, and the response rate for the questionnaires was 71.0%. RESULTS: By the end of 2010, in the 31 provincial-level regions (excluding Hong Kong, Macao, and Taiwan) in China, there had been 503 medical and health institutions which were qualified for providing occupational disease diagnosis, including 207 centers for disease control and prevention, accounting for 41.2%, 145 general hospitals, accounting for 28.8%, 69 enterprise-owned hospitals, accounting for 13.7%, and 64 institutes or centers for occupational disease prevention and control, accounting for 12.7%; 4986 certified doctors got the qualification for providing occupational disease diagnosis, with 9.4 certified doctors on average in each institution, and there was 0.65 certified doctor per 100 000 employees. In addition, 16.5% of the institutions got all the qualifications for diagnosing 9 occupational diseases, and 17.1% of the institutions got the qualification for diagnosing one occupational disease. Each certified doctor accepted diagnosis of 16.8 cases of occupational diseases on average every year. CONCLUSION: A national occupational disease diagnosis network has been established in China, but the imbalance in regional distribution and specialty programs still exists among the qualified medical and health institutions and certified doctors. It is essential to further strengthen the development of regional qualified medical and health institutions and training of qualified doctors.