In situ generation of copper(Ⅱ)/diethyldithiocarbamate complex through tannic acid/copper(Ⅱ) network coated hollow mesoporous silica for enhanced cancer chemodynamic therapy

The Cu2+ complex formed by the coordination of disulfiram (DSF) metabolite diethyldithiocarbamate (DTC), Cu(DTC)2, can effectively inhibit tumor growth. However, insufficient Cu2+ levels in the tumor microenvironment can impact tumor-suppressive effects of DTC. In this study, we proposed a Cu2+ and DSF tumor microenvironment-targeted delivery system. This system utilizes hollow mesoporous silica (HMSN) as a carrier, after loading with DSF, encases it using a complex of tannic acid (TA) and Cu2+ on the outer layer. In the slightly acidic tumor microenvironment, TA/Cu undergoes hydrolysis, releasing Cu2+ and DSF, which further form Cu(DTC)2 to inhibit tumor growth. Additionally, Cu2+ can engage in a Fenton-like reaction with H2O2 in the tumor microenvironment to form OH, therefore, chemodynamic therapy (CDT) and Cu(DTC)2 are used in combination for tumor therapy. In vivo tumor treatment results demonstrated that AHD@TA/Cu could accumulate at the tumor site, achieving a tumor inhibition rate of up to 77.6 %. This study offers a novel approach, circumventing the use of traditional chemotherapy drugs, and provides valuable insights into the development of in situ tumor drug therapies.

pH/glutathione dual-responsive copper sulfide-coated organic mesoporous silica for synergistic chemo-photothermal therapy

Nanodrug delivery systems (NDSs), such as mesoporous silica, have been widely studied because of their high specific surface area, high loading rate, and easy modification; however, they are not easily metabolized and excreted by the human body and may be potentially harmful. Hence, we aimed to examine the synergistic anti-tumor effects of ex vivo chemo-photothermal therapy to develop a rational and highly biocompatible treatment protocol for tumors. We constructed a biodegradable NDS using organic mesoporous silica with a tetrasulfide bond structure, copper sulfide core, and folic acid-modified surface (CuS@DMONs-FA-DOX-PEG) to target a tumor site, dissociate, and release the drug. The degradation ability, photothermal conversion ability, hemocompatibility, and in vitro and in vivo anti-tumor effects of the CuS@DMONs-FA-DOX-PEG nanoparticles were evaluated. Our findings revealed that the nanoparticles encapsulated in copper sulfide exhibited significant photothermal activity and optimal photothermal conversion rate. Further, the drug was accurately delivered and released into the target tumor cells, annihilating them. This study demonstrated the successful preparation, safety, and synergistic anti-tumor effects of chemo-photothermal therapeutic nanomaterials.

Fabrication of a novel low-cost superoleophilic nonanyl chitosan-poly (butyl acrylate) grafted copolymer for the adsorptive removal of crude oil spills

A novel superoleophilic-hydrophobic nonanyl chitosan-poly (butyl acrylate) grafted copolymer was fabricated as a low-cost oil-adsorbent. Chitosan (CS) was coupled with a hydrophobic nonanal (N) to form nonanyl chitosan (NCS) schiff base, and followed by grafting with butyl acrylate monomers (ButA). The grafted copolymer was characterized by FTIR, TGA and SEM tools. The grafting percent was augmented and reached 88.5% with increasing ButA concentration up to 156 mM. Moreover, measurements of contact angle proved the superoleophilic character of NCS-g-poly (ButA) copolymer with an oil-contact angle 31°. Factors affecting the removal process such as contact time, oil type, oil dose, adsorbent dose, temperature and agitation speed were optimized. An increment in the oil removal (%) was observed with increasing the oil viscosity in the order of gasoil < mobil-1 oil < light crude oil < heavy crude oil. Besides, the adsorption process followed the pseudo-second order model and the equilibrium data were sufficiently fitted with the Langmuir model with a maximum adsorption capacity 108.79 g/g at 25 °C. Thermodynamic parameters computed from Van't Hoff plot confirmed the process to be exothermic, favorable and spontaneous. The results nominate the superoleophilic adsorbent as a potential oil- adsorbent for petroleum oil spills removal.

Efficient adsorption of diclofenac sodium from aqueous solutions using magnetic amine-functionalized chitosan

In this study, we prepared a magnetic composite based on amine-functionalized chitosan (aminochitosan; AmCS) and Fe₃O₄ to remove diclofenac sodium (DS) from water. The fabricated AmCS@Fe₃O₄ composite was characterized using Fourier-transform infrared spectroscopy, transmission electron microscopy, scanning electron microscopy, vibrating sample magnetometry, X-ray diffraction, and thermogravimetric analysis. Furthermore, we investigated the influence of pH, initial DS concentration, and adsorbent dosage on the adsorption of DS. Through thermodynamic analysis, we found that the data corresponded with the Langmuir adsorption isotherm model. The maximum adsorption capacity reached 469.48 mg g^-1, and the adsorption process followed the pseudo-second-order kinetic model. Finally, the AmCS@Fe₃O₄ composite retained good adsorption characteristics after four consecutive cycles, with removal efficiency exceeding 70%. Therefore, the developed adsorbent could be used for efficient adsorptive removal of trace drugs and personal care products from water bodies.