Fenton-Reaction-Derived Fe/N-Doped Graphene with Encapsulated Fe3C Nanoparticles for Efficient Photo-Fenton Catalysis

A hypoxia-activated and tumor microenvironment-remodeling nanoplatform for augmenting sonodynamic-chemodynamic-chemotherapy of breast cancer

The tumor microenvironment (TME) offers a promising approach to enhancing cancer therapy by altering the conditions that support tumor growth and immune evasion. However, tumors are highly heterogeneous, and the TME can vary greatly even within different regions of the same tumor. Moreover, tumors can have evolving resistance mechanisms that limit the effectiveness of therapies. In this paper, we have designed a multifunctional nanoparticle named Lip-Ce6-MnO2-TPZ, making sonodynamic therapy (SDT), chemodynamic therapy (CDT), and hypoxia-activated prodrugs work synergistically to maximize cancer treatment efficacy. The innovative Lip-Ce6-MnO2-TPZ nanoparticle was constructed by loading Ce6, MnO2, and hypoxia responsive drug tirapazamine (TPZ) together into a cytotoxic reactive oxygen species (ROS) responsive nanocarrier. Upon ultrasound (US) irradiation, ROS generated by Ce6 could not only induce cell apoptosis but also accelerate the disassembly of the nanoparticle for enhancing the release of TPZ and MnO2. As a result, SDT consumed oxygen leading to the aggravation of the hypoxic condition in the tumor site for TPZ activation and DNA damage in tumor cells. Meanwhile, the MnO2 was reduced to Mn2+ by GSH and caused antioxidant depletion. Mn2+ triggered CDT through a Fenton-like reaction by converting H2O2 to highly toxic •OH. Overall, the Lip-Ce6-MnO2-TPZ platform could induce the generation of excess ROS combined with antioxidant depletion, resulting in oxidative stress and aberrant redox homeostasis of the TME. This strategy has brought forward the idea of inducing cancer cell death by synergistically working SDT, CDT, and hypoxia-activated prodrugs to maximize the therapeutic efficacy in cancer treatment.

Constructing Stable N-Doped Iron-Based Porous Carbon Nanocatalyst for Antibiotic Degradation and Bactericidal Detoxification

N-doped iron-based carbon is a promising catalyst to achieve peroxydisulfate (PDS) activation, but constructing efficient and stable N-doped iron-based carbon catalysts with uniformly distributed and firmly anchored nitrogen and iron sources remains challenging. Herein, we developed a stable N-doped magnetic porous carbon (NMPC) catalyst through self-polymerization and high-temperature pyrolysis of polydopamine and Fe3+ coordination complexes and explored it for PDS activation in antibiotic (tetracycline (TC) and ciprofloxacin) degradation and bactericidal detoxification. The NMPC/PDS system performed both radical and nonradical catalytic pathways for effective PDS activation, exhibiting 99.8% removal of TC. Thanks to the strong coordination of polydopamine with Fe3+, the resulting NMPC could firmly confine iron species in the porous N-carbonaceous matrices and efficiently prevent severe iron leaching, demonstrating good recyclability. It could maintain a removal rate as high as 92.4% after 5 cycles. After cycling, the iron leaching of the NMPC catalyst is only 0.026 mg/L, which is much lower than the WHO guideline value limits for drinking water of 0.3 mg/L. Moreover, the NMPC catalyst exhibits excellent stability and compatibility with various water conditions, including pH variations (3-9), coexisting substances, and different water sources. In addition, this NMPC/PDS system exhibits an excellent disinfection of both Escherichia coli and Staphylococcus aureus, with a high disinfection ratio of more than 99.9%. Toxic intermediate prediction and cell toxicity experiments further prove that the toxicity of the TC wastewater is significantly reduced after the treatment with the NMPC/PDS system.

Application of Optimization Response Surface for the Adsorption of Methylene Blue Dye onto Zinc-coated Activated Carbon

The activated carbon was produced in the first phase of this investigation by chemically activating hazelnut shell waste with H3PO4. Composite materials were obtained by coating the activated carbon with zinc oxide, whose BET surface area was calculated as 1278 m2 g-1. ZnO-doped ZnO/AC composite was synthesized as an adsorbent for its possible application in the elimination of organic dyestuff MB, and its removal efficiency was investigated. Morphological properties of ZnO/AC were characterized using analytical methods such as XRD, SEM, and BET. The adsorption system and its parameters were investigated and modeled using the response surface method of batch adsorption experiments. The experimental design consisted of three levels of pH (3, 6.5, and 10), initial MB concentration (50, 100, and 150 mg L-1), dosage (0.1, 0.3, and 0.5 g 100 mL-1), and contact time (5, 50, and 95 min). The results from the RSM suggested that the MB removal efficiency was 98.7% under the optimum conditions of the experimental factors. The R2 value, which expresses the significance of the model, was determined as 99.05%. Adsorption studies showed that the equilibrium data fit well with the Langmuir isotherm model compared to Freundlich. The maximum adsorption capacity was calculated as 270.70 mg g-1.

A green approach of biochar-supported magnetic nanocomposites from white tea waste: Production, characterization and plausible synthesis mechanisms

Green synthesized magnetic nanoparticles were impregnated into biochar matrix (EWTWB) to produce biochar-supported magnetic nanocomposite (GSMB). Instead of chemicals, organic matters in white tea waste extract were used as reductant, surfactant and functional capping materials. Magnetic biochar produced from traditional methods of pyrolysis (PMB) and co-precipitation (Co-PreMB) were prepared to compare their properties with GSMB. Xray Diffraction confirmed the main component of green synthesized particles is Fe₃O₄. When compared with PMB and Co-PreMB, the Fe₃O₄ produced by co-precipitation method has higher purity while the products from green synthesis method are complex and contain a small portion of other iron-containing compounds. As a consequence, Co-PreMB has higher saturation magnetisation value than GSMB, which are 31.3 and 11.5 Am²/kg, respectively. GSMB was also found to be less stable in acidic conditions (pH ≤ 4) than Co-PreMB. However, the SEM results exhibited that spherical magnetic nanoparticles (20-50 nm) were successfully formed and distributed on the surface of biochar via green synthesis method while serious aggregation happened on the surface of Co-PreMB. According to the result of BET, the surface area of GSMB increased dramatically from 0.2 m²/g to 59.7 m²/g. Fourier Transform Infrared spectroscopy and Xray photoelectron spectroscopy results showed the presence of rich oxygen-containing functional groups on the GSMB The high surface area and rich functional groups making the green synthesis method a very promising greener way to prepare magnetic biochar for the purpose of wastewater treatment.