Ion is one of the most common additives that can impart electrical conductivity to insulating hydrogels. The concurrent toughening effect of ions, however, is often neglected. This work reports the extreme toughening of hydrogels via the synergistic effect of cations and anions, without the need for specific structure design or adding other reinforcements. The strategy is to equilibrate a physical double network hydrogel consisting of both multivalent cation-and kosmotropic anion-sensitive polymers in specific salt solutions that can induce cross-linking and salting-out simultaneously. Both effects are proven positive to boost the mechanical performance and electrical conductivity of the original weak gel, and result in a tough conductive gel with exceptional physical properties, achieving significant enhancements in fracture stress, fracture energy, and ionic conductivity by up to 530-, 1100-, and 4.9-folds, respectively. The optimal fracture stress and toughness reach approximately 15 MPa and 39 kJ m -2 , exceeding most state-of-the-art tough conductive hydrogels. Meanwhile, a satisfactory ionic conductivity of 1.5 S m -1 is attained. The presented simple strategy is also found generalizable to other salt ions and polymers, which is expected to expand the applicability of hydrogels to conditions involving demanding mechanical durability.

The development of an efficient delivery system for enhanced and controlled gene interference–based therapeutics is still facing great challenges. Fortunately, the flourishing field of nanotechnology provides more effective strategies for nucleic acid delivery. Here, the triplex-forming oligonucleotide sequence and its complementary strand were used to mediate self-assembly of ultrasmall gold nanoparticles. The obtained sunflower-like nanostructures exhibited strong near-infrared (NIR) absorption and photothermal conversion ability. Upon NIR irradiation, the large-sized nanostructure could disassemble and generate ultrasmall nanoparticles modified with c-myc oncogene silencing sequence, which could directly target the cell nucleus. Moreover, the controlled gene silencing effect could be realized by synergistically controlling the preincubation time with the self-assembled nanostructure (in vitro and in vivo) and NIR irradiation time point. This study provides a new approach for constructing more efficient and tailorable nanocarriers for gene interference applications.

No abstract

Reaction of 2,6-bis(3-butylbenzimidazol-1-ium)pyridine dibromide with silver oxide affords a dinuclear complex of the type [L 2 Ag 2 ] 2+ [L = 2,6-bis(3-butylbenzimidazolin-2ylidene)pyridine]. 1 H NMR spectroscopic studies suggest that the dinuclear structure is also present in solution. Transmetallation of the silver-NHC complex with PdCl 2 (CH 3 CN) 2 yields a mononuclear palladium complex of the type [LPdCl] + , with a chelating C,N,C-pincer ligand.

The inflammatory cytokine interleukin-6 (IL-6) is a causative agent of rheumatoid arthritis (RA), a chronic inflammatory disease complicated with degenerative arthritic cartilage. However, the precise mechanism of IL-6 on chondrocyte apoptosis is largely unclear. Acid-sensing ion channels (ASICs), a family of extracellular H(+)-activated cation channels, can be transiently activated by extracellular acid and play a pivotal role in acid-induced cell injury. In the present study, to investigate the role of IL-6 in regulating acid-induced articular chondrocyte apoptosis, primary rat articular chondrocytes were subjected to different treatments with or without IL-6 in the presence of acid. The results showed that the mRNA and protein expressions of ASIC1a were significantly increased in articular cartilage and chondrocytes of adjuvant arthritis (AA) rats. IL-6 could dramatically upregulate the level of ASIC1a in a time- and dose-dependent manner, and induce the activation of JAK2, STAT3, ERK, JNK and NF-κB in articular chondrocytes. Moreover, both the respective inhibitors of these signaling pathways and the specific antibody against IL-6 receptor (tocilizumab) could partially abrogate the ASIC1a upregulation induced by IL-6. Furthermore, IL-6 inhibited the cell viability and enhanced LDH release, [Ca(2+)]i elevation, and apoptosis in acid-induced articular chondrocytes, and these changes could be reversed by using psalmotoxin 1(PcTX1), which is the specific antagonist of ASIC1a. In addition, pretreatment with PcTX1 could inhibit the downregulated expression of Bcl-2 and the upregulated expression of Bax induced by IL-6 in acid-induced articular chondrocytes. Taken together, these results indicated that IL-6 could enhance acid-induced articular chondrocyte apoptosis, the mechanism of which might partially be involved with its ability of regulating the activation of ASIC1a-dependent JAK2/STAT3 and MAPK/NF-κB signaling pathways.

Swelling is ubiquitous for conventional hydrogels but is not favorable for many situations, especially underwater applications. In this study, an antiswelling and mechanically robust polyacrylic acid (PAAc)/gelatin composite hydrogel is reported with a rapid gelation process (10 1 s) under mild conditions via the synergy of MXene-activated initiation and zirconium ion (Zr 4+ )-induced cross-linking, without the requirement of external energy input. The MXene is found efficient to activate the chain initiation, while the Zr 4+ is prone indispensable for facilitating the cross-linking of formed polymer chains. The resulting hydrogel exhibits integration of exceptional anti-swelling properties and high mechanical performance at room temperature, thanks to the dense hydrogen bonds between PAAc and gelatin chains that enable an upper critical solution temperature above room temperature. Also, desirable electrical conductivity emerges in the hydrogel due to the simultaneous contribution of MXene and Zr 4+ , allowing stable electrical signal output of the gel upon deformation underwater. As a demonstration, an underwater communicator by harnessing the gel as a sensing module is assembled, which is capable of wirelessly delivering messages to the decoder on the ground via Morse codes. This study provides an exemplary way for the rapid gelation of tough and anti-swelling hydrogels for durable underwater applications.

No abstract

No abstract