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Inflammatory responses of nucleus pulposus (NP) can induce imbalanced anabolism and catabolism of extracellular matrix, and the cytosolic dsDNA accumulation and STING–NF–κB pathway activation found in NP inflammation are considered as fairly important cause of intervertebral disc (IVD) degeneration. Herein, we constructed a siSTING delivery hydrogel of aldehyde hyaluronic acid (HA-CHO) and poly(amidoamine) PAMAM/siRNA complex to intervene the abnormal STING signal for IVD degeneration treatment, where the formation of dynamic Schiff base bonds in the system (siSTING@HPgel) was able to overcome the shortcomings such as low cellular uptake, short half-life, and rapid degradation of siRNA-based strategy. PAMAM not only formed complexes with siRNA to promote siRNA transfection, but also served as dynamic crosslinker to construct hydrogel, and the injectable and self-healing hydrogel efficiently and steadily silenced STING expression in NP cells. Finally, the siSTING@HPgel significantly eased IVD inflammation and slowed IVD degeneration by prolonging STING knockdown in puncture-induced IVD degeneration rat model, revealing that STING pathway was a therapeutic target for IVD degeneration and such novel hydrogel had great potential for being applied to many other diseases for gene delivery., Graphical abstract Image 1, Highlights • STING-NF-κB pathway activation was identified an important cause of intervertebral disc degeneration. • PAMAM was employed as both linker and gene vector for siRNA delivery. • The injectable self-healing hydrogel could significantly ease the IVD inflammation and degeneration by prolonging STING knockdown. • This novel hydrogel system opened new ways of thinking and had great potential for gene delivery.

Photocatalytic mineralization of dimethoate using nanosized TiO2 at different conditions has been investigated. The objective of this work was to study the influence on the photocatalytic mineralization of dimethoate, of various parameters and identify intermediates formed during photocatalytic treatment. The mineralization efficiency of dimethoate increased with elevated concentration of humic acid up to 5 mg/L, while the efficiency reduced when the concentration was above 5 mg/L due to competitive adsorption. The presence of CH3COCH3 can significantly inhibit dimethoate mineralization and the half-life of mineralization efficiency was increased by about 3 times. The photo mineralization efficiency changed with increasing concentrations of inorganic ions. With respect to the ions of Fe3+, Cu2+, Zn2+, HCO3− and NO3−, the mineralization efficiency increased with increasing concentration of ions and reached a maximum at optimal concentrations, which was followed by a decrease with a further increase in ion concentrations. By contrast, the mineralization of dimethoate was strongly inhibited by Cl− and Cr3+ ions. Intermediate products from dimethoate were identified by means of GC–MS and four possible by-products were identified. A proposed mineralization pathway for dimethoate is presented.

The adsorption equilibria of single-component and binary mixtures of levulinic/formic acids in the aqueous solution on three different types of basic polymeric adsorbents were experimentally measured at 30 °C. Adsorption isotherms such as Langmuir, Freundlich and Sips were applied to correlate the single-solute adsorption data. Results demonstrated that the adsorption isotherms of both acids on all three adsorbents were best described by the Sips model, and that formic acid has higher adsorption capacity and stronger affinity on all three resins. The adsorption of binary mixtures of formic/levulinic acids reveals that formic acid is preferentially adsorbed and levulinic acid can be competitively displaced by formic acid. Binary Sips model and the ideal adsorbed solution (IAS) theory were employed to simulate the binary competitive adsorption data. The binary Sips model cannot predict the competitive adsorption behavior. The IAS model was successfully coupled with Sips isotherm parameters determined from single-component adsorption data to predict the binary competitive adsorption behavior of levulinic/formic acids on all three resins.