An efficient disposable and flexible electrochemical sensor based on a novel and stable metal carbon composite derived from cocoon silk

Abstract(#br)The present work reports cocoon silk fibroin (SF)as a unique precursor for the in-situ fabrication of well-engineered, stable and leach free gold nanoparticle doped carbonaceous materials (AuNPs@NSC). In principle, at the molecular level, SF has a singular structure that can be converted to a N-doped aromatic carbon structure by heat treatment. The electrochemical properties of the prepared nanocomposite were examined by cyclic voltammetry and differential pulse voltammetry. A flexible three electrode sensor system with AuNPs@NSC-modified working electrodes has been developed, to achieve easy operation and quick and accurate responses. The electrochemical results showed that the sensor made by the AuNPs@NSC-modified working electrode demonstrated high sensitivity for the detection of rutin, which is attributed to the good distribution of the AuNPs on the carbon matrix. Using differential pulse voltammetry (DPV), the AuNPs@NSC electrode was found to have a linear response in the range of 0.11–250 μM and a comparably low limit of detection of 0.02 μM (S/N = 3). To ensure the accuracy and applicability of the sensors, the concentration of rutin in the commodity (rutin capsule, 10 mg/capsule) was examined, and the sensor provided high precision with a minimum relative error (RE) of 3.3%. These findings suggest that AuNPs@NSC can be considered to be a potential electrode material for the development of electrochemical devices and has great potential in extending their application to the flexible sensor field

A Novel Facile and Green Synthesis Protocol to Prepare High Strength Regenerated Silk Fibroin/SiO 2 Composite Fiber

Abstract(#br)In this work, regenerated silk fibroin (RSF) and silicon dioxide (SiO 2 ) composite fiber was successfully extruded by wet spinning method. The effect of SiO 2 addition on structure of the composite fiber at microscopic level is studied, which subsequently correlated to the mechanical performance. The best concentration ratio for composite fiber is identified by screening SiO 2 concentration from 0.025 w/w% to 0.5 w/w%. The experimental results revealed that the SiO 2 at a low concentration of 0.1 w/w% was well distributed. The breaking stress, breaking strain and Young’s modulus at 0.1 w/w% SiO 2 addition of the RSF fibers increased considerably compared to the neat RSF fibers from 243±3 to 458±21 MPa, 51±4 % to 54±7 % and 6.34±0.55 to 11.69±1.12 GPa, respectively. To the..

上转换荧光点亮软物质体内成像新思路

传统的非侵入性活体生物成像技术主要是基于计算机断层扫描和核磁共振成像等技术，这些技术由于其相对较低的分辨率和对组织的损伤而受到限制。通过从介观尺度将稀土上转换纳米颗粒均匀地组装到丝素蛋白生物支架，使其具备在近红外激发下产生可见光波段发射光的上转换荧光性能。该团队使用低功率连续980 nm波长的近红外激光穿透大鼠皮肤和组织、激发植入的蚕丝丝素生物支架，产生可见光（绿光）图像。揭示了蚕丝生物支架的生物相容性、力学性能和生物降解性，以及组织细胞与生物支架的相互作用。丝素蛋白生物支架是一种软物质，上转换荧光技术为体内软物质成像提供了新思路。【中文摘要】首次采用上转换荧光技术实现了丝素蛋白生物支架体内生物成像，解决了传统体内软物质材料生物成像难以实现实时、高分辨、深穿透和低损伤的局限。【Abstract】In biomedical applications, it is very desirable to monitor the in vivo state of implanted devices, i.e., tracking the location, the state, and the interaction between the implanted devices and cell tissues. To achieve this goal, a generic strategy of soft materials meso-functionalization is presented. This is to acquire silk fibroin (SF) materials with added functions, i.e., in vivo bioimaging/sensing. The functionalization is by 3D materials assembly of functional components, lanthanide(Ln)-doped upconversion nanoparticles (UCNPs) on the mesoscopic scale to acquire upconversion fluorescent emission. To implement the meso-functionalization, the surfaces of UCNPs are modified by the hydroxyl groups (—OH) from SiO2 or polyethylene glycol coating layers, which can interact with the carbonyl groups (C==O) in SF scaffolds. The functionalized silk scaffolds are further implanted subcutaneously into mice, which allows the silk scaffolds to have fluorescent in vivo bioimaging and other biomedical functions. This material functionalization strategy may lead to the rational design of biomaterials in a more generic way.The work was supported by the 111 Project (Grant No. B16029), National Natural Science Foundation of China (Grant Nos. 21404087, 61674050, and U1405226), Fujian Provincial Department of Science and Technology (Grant Nos. 2017J06019, 2014H6022, and 2015J05109), Natural Science Foundation of Guangdong Province (Grant No. 2015A030310007), 1000 Talents Program, and President Foundation from Xiamen University (Grant No. 20720160088), NUS tear 1 funding (WBS: R-144-000-367-112)

Discovery of 5-(5,5-Dimethylbutenolide-3-ethylidene)-2-amino-imidazolinone Derivatives as Fungicidal Agents

The novel fungicidal agents 5-(5,5-dimethylbutenolide-3-ethylidene)-2-amino-imidazolinone derivatives, were designed and synthesized in moderate to excellent yields in four steps by αa-hydroxyketone and diketene as raw materials and characterized by HR-ESI-MS and 1H-NMR. The preliminary bioassay showed that some of these compounds, such as 4a, 4e and 5g exhibit 94.9%, 92.8% and 81.4% inhibition rates against Sclerotinia scleotiorum at the concentration of 50 µg/mL, respectively. The EC50 values of compounds 4e and 4i were 4.14 and 3.27 µM against Alternaria Solani, and 5g had EC50 value of 3.23 µM against S. scleotiorum. Compounds 4d and 4g displayed 98.0% and 97.8% control of spore germination against Botrytis cinerea at the concentration of 100 µg/mL, respectively