Preparation of a pH-responsive chitosan-montmorillonite-nitrogen-doped carbon quantum dots nanocarrier for attenuating doxorubicin limitations in cancer therapy.

Despite its widespread usage as a chemotherapy drug in cancer treatment, doxorubicin (DOX) has limitations such as short in vivo circulation time, low solubility, and poor permeability. In this regard, a pH-responsive chitosan (CS)- montmorillonite (MMT)- nitrogen-doped carbon quantum dots (NCQDs) nanocomposite was first developed, loaded with DOX, and then incorporated into a double emulsion to further develop the sustained release. The incorporated NCQDs into the CS-MMT hydrogel exhibited enhanced loading and entrapment efficiencies. The presence of NCQDs nanoparticles in the CS-MMT hydrogel also resulted in an extended pH-responsive release of DOX over a period of 96 h compared to that of CS-MMT-DOX nanocarriers at pH 5.4. Based on the Korsmeyer-Peppas model, there was a controlled DOX release at pH 5.4, while no diffusion was observed at pH 7.4, indicating fewer side effects. MTT assay showed that the cytotoxicity of DOX-loaded CS-MMT-NCQDs hydrogel nanocomposite was significantly higher than those of free DOX (p < 0.001) and CS-MMT-NCQDs (p < 0.001) on MCF-7 cells. Flow cytometry results demonstrated that a higher apoptosis induction achieved after incorporating NCQDs nanoparticles into CS-MMT-DOX nanocarrier. These findings suggest that the DOX-loaded nanocomposite is a promising candidate for the targeted treatment of cancer cells.

Antibacterial properties of a bacterial cellulose CQD-TiO2 nanocomposite.

Antibacterial dressing can prevent the occurrence of many infections of wounds. Bacterial cellulose (BC) has the ability to carry and transfer the medicine to achieve a wound healing bandage. In this study, Carbon Quantum Dots-Titanium dioxide (CQD-TiO2) nanoparticles (NP) were added to BC as antibacterial agents. FTIR Spectroscopy illuminated that NPs were well-bonded to BC. Interestingly, MIC test proved that BC/CQD-TiO2 nanostructure (NS) has anti-bacterial properties against Staphylococcus aureus. The findings indicated that, CQD-TiO2 NPs have stronger antibacterial properties with better tensile strength compared to CQD NPs, in a concentration-dependent manner. Toxicity of CQD-TiO2 NPs on human L929 fibroblast cells was also evaluated. Most importantly, the results of the scratch test indicated that the NS was effective in wound healing in L929 cells. The approach in this study may provide an alternative to make an antibacterial wound dressing to achieve an effective drug-based bandage.