A dual-modal colorimetric and photothermal assay for glutathione based on MnO2 nanosheets synthesized with eco-friendly materials.

We developed a dual-modal colorimetric and photothermal assay for glutathione (GSH) using MnO2 nanosheets prepared with environmentally friendly materials. The nanosheets were synthesized by using ascorbic acid present abundantly in lemon and orange juices to reduce KMnO4. The as-prepared MnO2 nanosheets display oxidase-like activity and can catalyze the oxidation reaction of 3,3',5,5'-tetramethylbenzidine (TMB), yielding a blue oxidative product (oxTMB) that exhibits a UV-Vis absorption peak at 652 nm. In the presence of GSH, the MnO2 nanosheets are reduced and decomposed, resulting in a decrease in the peak intensity. The colorimetric assay offers a wide dynamic range (0.1-100 µM) and a detection limit of 100 nM. The MnO2 nanosheets are also efficient in converting photoenergy to thermal energy, with a photothermal conversion efficiency of 23.3%. The temperature change, after near-infrared (NIR) irradiation at 808 nm, can be easily measured by an inexpensive pen-type thermometer. This effect can also be used for GSH quantification and expands the GSH concentration detection to the range from 6.0 to 200 µM. The viability of our dual-modal assay for clinical applications was demonstrated with successful analyses of GSH in human serum samples. Graphical abstract.

Fabrication of pH-responsive temozolomide (TMZ)-clacked tannic acid-altered zeolite imidazole nanoframeworks (ZIF-8) enhance anticancer activity and apoptosis induction in glioma cancer cells.

Glioma cancer is the primary cause of cancer-related fatalities globally for both men and women. Traditional chemotherapy treatments for this condition frequently result in reduced efficacy and significant adverse effects. This investigation developed a new drug delivery system for the chemotherapeutic drug temozolomide (TMZ) using pH-sensitive drug delivery zeolitic imidazolate frameworks (ZIF-8). These nanoplatforms demonstrate excellent biocompatibility and hold potential for cancer therapy. Utilizing the favorable reaction milieu offered by ZIFs, a 'one-pot method' was employed for the fabrication and loading of drugs, leading to a good capacity for loading. TMZ@TA@ZIF-8 NPs exhibit a notable response to an acidic milieu, resulting in an enhanced drug release pattern characterized by a controlled release outcome. The effectiveness of TMZ@TA@ZIF-8 NPs in inhibiting the migration and invasion of U251 glioma cancer cells, as well as promoting apoptosis, was confirmed through various tests, including MTT (3-(4,5)-dimethylthiahiazo(-z-y1)) assay, DAPI/PI dual staining, and cell scratch assay. The biochemical fluorescent staining assays showed that TMZ@TA@ZIF-8 NPs potentially improved ROS, reduced MMP, and triggered apoptosis in U251 cells. In U251 cells treated with NPs, the p53, Bax, Cyt-C, caspase-3, -8, and -9 expressions were significantly enhanced, while Bcl-2 expression was diminished. These outcomes show the potential of TMZ@TA@ZIF-8 NPs as a therapeutic agent with anti-glioma properties. Overall, the pH-responsive drug delivery systems we fabricated using TMZ@TA@ZIF-8 NPs show great potential for cancer treatment. This approach has the potential to make significant contributions to the improvement of cancer therapy by overcoming the problems associated with TMZ-based treatments.