Reactive oxygen species (ROS) play crucial roles in cell signaling and redox homeostasis and are strongly related to metabolic activities. The increase of the ROS concentration in organisms can result in several diseases, such as cardiovascular diseases and cancer. The concentration of ROS in biologically relevant conditions is typically as low as around tens of micromolars to 100 μM H2O2, which makes it necessary to develop ultrasensitive ROS-responsive systems. A general approach is reported here to fabricate an ultrasensitive ROS-responsive system via coassembly between tellurium-containing molecules and phospholipids, combining the ROS-responsiveness of tellurium and the biocompatibility of phospholipids. By using dynamic light scattering, transmission electron microscopy, scanning electron microscopy, and NMR spectra, coassembly behaviors and the responsiveness of the coassemblies have been investigated. These coassemblies can respond to 100 μM H2O2, which is a biologically relevant ROS concentration, and demonstrate reversible redox properties.
Dual physical network hydrogel possesses robust energy dissipation mechanism. However, the demanding conditions of the second monomer radical polymerization aren't benefit for the dispersion of conductive filler. Moreover, the stable and sensitive response under extreme environment puts forward the requirements for mechanical, antifreezing and moisture retention properties. Herein, a dual physical networks hydrogel (polyacrylic acid-chitosan-graphene/glycerol, noted as PAA-CS-G/Gly) was prepared rapidly (<0.5 h) without chemical cross-linking agents at room temperature. The rapid gelation, ionic coordination of Ag + together with certain viscosity chitosan promoted the dispersion of graphene. PAA-CS-G/Gly showed ultra-stretchable properties (~2500%), good toughness (3.11 MJ/m 3 ), breaking strength (0.27 MPa) and fatigue resistance. PAA-CS-G/Gly had good adhesion properties, outstanding tolerance for freezing (−80°C) and moisture retention. More importantly, PAA-CS-G/Gly strain sensor had excellent sensitivity (GF, up to 9.449) at 300% ~ 900% strain. It could sensitively detect human joint movements and even subtle activities such as talking and swallowing. PAA-CS-G/Gly hydrogel is expected to adhere directly to the human body for flexible monitoring of human size movement under extreme environmental conditions.
The accurate detection of the superoxide anion (O 2 •− ) has vital academic and medical diagnostic significance due to its important dual roles in biological functioning. In this work, hollow porous PtAg nanospheres (PtAg HPNSs) were fabricated by a facile hydrothermal method followed by a dealloying procedure. The as-made PtAg nanospheres possessed hollow interiors and porous shells composed of interconnected ligaments and pores with the typical size around 4 nm. Benefitting from the unique hollow nanoporous architecture and the specific alloying effect, the PtAg HPNSs showed high electrocatalytic activity towards superoxide anions. The constructed biosensor based on PtAg HPNSs presented a fast and ultrasensitive response in a wide range of 0.8–1080 nM with much higher sensitivity of 4.5 × 10 −2 μA cm −2 nM −1 and low detection limit of 0.2 nM (S/N = 3). Moreover, the novel biosensors can achieve electrochemical detection for O 2 •− released from living cells, exhibiting outstanding real time detection capability in cell environment. The facile controllable fabrication and unique sensing performance for PtAg HPNSs offers potential practical applications in developing highly sensitive and stable biosensor towards superoxide anion.
危险品化学品经营许可证（带存储）