Northeast Normal University

Antimicrobial hydrogels that can effectively eliminate microorganisms to accelerate wound healing have demostrated great potential in managing wound infections. However, conventional hydrogel dressings have limited contact with bacteria due to their permemnent cross-linked structure, thereby reducing their bactericidal efficiency. To address this issue, we designed and prepared a neutrophil extracellular traps (NETs) biomimetic antibacterial hydrogel (PETP gel) with enhanced bacteria contact and bactericidal efficiency through Schiff base crosslinking of antibacterial polymer PETP-NH₂ and phenylboronic acid functionalized oxidized hyaluronic acid (OHA-PBA). The obtained PETP gel exhibited a NETs-mimicking dynamic filamentous network structure, which, in combination with the interaction between phenylboronic acid in OHA-PBA and lipopolysaccharides in bacterial surface, ultimately led to enhanced bacteria contact and bactericidal efficiency. In vivo experiments showed that PETP gel could accelerate healing in treatment of purulent subcutaneous infection, full-thickness wound infection, and deep second-degree burn infection, showing promising use as an antibacterial care dressing.

Stable NO₂^- supply and low-temperature inhibition represent two major bottlenecks for anaerobic ammonia oxidation (anammox) in mainstream wastewater treatment. It was reported that applied electric fields enable anaerobic ammonium-oxidizing bacteria (AnAOB) to directly oxidize NH₄⁺ to N₂. Whereas, low-temperature inhibition primarily stems from impaired electron transfer and subsequent metabolic suppression. Enhancing these processes through applied potential and conductive materials offers a strategy for this study. A single-chamber microbial electrolysis cell with 0.6 V anodic potential and 10 mg L^-1 reduced graphene oxide (RGO) was developed. Results showed that the system achieved nitrogen removal rates of 7.4 ± 0.5g N m^-3 d^-1 and 74.2 ± 4.8 mg N m^-2 d^-1 at 10°C. NH₄⁺-N and total nitrogen removal efficiencies increased by 116.6% and 147.0%, respectively. The applied potential upregulated pili/cytochrome expression, while the RGO network provided a low-resistance conductive matrix. As a result, synergic system effectively intensified electron transfer, which increased anode current density by 1.9-fold and reduced resistance by 67.7%, supporting both conventional anammox via enhanced nitritation and the electric-anammox pathway. Furthermore, it also promoted the enrichment functional genes, such as hzs and hdh (107.6%-238.1%), and enhanced cold adaptation marked by increased in extracellular proteins and polysaccharides (44.8%-18.9%). This work demonstrates coordinated electron transfer enhancement and metabolic activation through potential-RGO integration provides an innovative solution for energy-efficient nitrogen removal in cold-region wastewater treatment.

Amino acid (AA)-based nanoparticles (NPs) hold promise in cancer therapy due to their excellent biocompatibility and the various therapeutic functions derived from AA monomers. Here, we developed a universal one-step method to synthesize AA-based NPs. We then constructed L-Arginine (L-Arg)/calcium phosphate (CaP) NPs to enhance cancer therapy through synergistic calcium overload to induce apoptosis and immunogenic cell death. The engineered L-Arg/CaP NPs rapidly degraded and released a large amount of exogenous calcium ions (Ca²⁺) in the acidic tumor microenvironment (TME). Notably, L-Arg-derived NO synergistically enhanced calcium overload through two distinct mechanisms: (1) induction of S-nitrosylation of the ryanodine receptor (RyR) on the endoplasmic reticulum (ER) to facilitate endogenous Ca²⁺ release, and (2) significant downregulation of plasma membrane Ca²⁺-ATPase (PMCA) expression to inhibit Ca²⁺ efflux. This unique three-level regulatory mechanism involving external Ca²⁺ supply, internal Ca²⁺ release, and efflux inhibition created a cascading amplification of intracellular Ca²⁺ concentration. Importantly, it overcame the limitations of tumor cell stress adaptation in conventional single-ion therapy, thereby establishing a new therapeutic paradigm. In vitro and in vivo studies confirmed that L-Arg/CaP NPs induce tumor suppression with excellent biosafety, indicating the potential for an innovative strategy integrating calcium overload and gas therapy for cancer treatment.