Facile synthesis of carbon/titanium oxide quantum dots from lignocellulose-rich mandarin orange peel extract via microwave irradiation: Synthesis, characterization and bio-imaging application.

A nanohybrid prepared from the lignocellulosic residue is a feasible approach to synthesize blue light emitting fluorescent doped TiO2 quantum dot nanocomposite (C-TiO2 QDs) by microwave techniques using Mandarin orange (Citrus reticulata) peel powder with titanium isopropoxide precursors. With a greater orange peel colloidal medium, the structure of the TiO2-NPs changed from a mixture of rutile and anatase phases to exclusively the anatase phase. The optical and morphological properties of as-prepared C-TiO2 QDs were characterized by HR-TEM, XRD, FT-IR, UV-visible, PL spectra, DLS, and Zeta potential techniques. The reaction condition was optimized by changing substrate composition, pH, and reaction time. C-TiO2 QDs exhibit outstanding stability at pH 7 and remain sustained for at least 180 days without aggregation. As prepared C-TiO2 QDs have distinct emission and excitation activities with an average particle size of 2.8 nm. Cell viability was performed on normal L929 cells, where it showed excellent biocompatibility (<90 %) even at the concentration of 200 µg/mL after 24 h treatment. Additionally, the synthesized C-TiO2 QDs were used with L929 cells as a fluorescent probe for bio-imaging applications. The results revealed that neither of the cell lines' morphologies had significantly changed, proving the biocompatibility of the synthetic C-TiO2 QDs.

Mitochondrial dysfunction-induced apoptosis in breast carcinoma cells through a pH-dependent intracellular quercetin NDDS of PVPylated-TiO2NPs.

In this article, we report the validation of cancer nanotherapy for the treatment of cancers using quercetin (Qtn). Much attention has been paid to the use of nanoparticles (NPs) to deliver drugs of interest in vitro/in vivo. Highly developed NPs-based nano drug delivery systems (NDDS) are an attractive approach to target cancer cell apoptosis, which is related to the onset and progression of cancer. Conventional chemotherapy has some notable drawbacks, such as lack of specificity, requirement of high drug doses, adverse effects, and gradual development of multidrug resistance (MDR), that decrease the efficacy of cancer therapy. To overcome these challenges of chemotherapy, the achievement of high drug loading in combination with low leakage at physiological pH, minimal toxicity toward healthy cells, and tunable controlled release at the site of action is an ongoing challenge. To assist drug delivery, we have prepared PVPylated-TiO2NPs containing Qtn with high loading efficiency (26.6% w/w) as a NDDS. The Qtn-PVPylated-TiO2NPs are uptaken via endocytosis by cancer cells and can generate intracellular reactive oxygen species (ROS) in order to increase mitochondrial membrane potential loss (Δψm) and enable release of cytochrome-c, followed by dysregulation of Bcl-2 into the cytosol and activation of caspase-3 to induce cancer cell apoptosis. These novel nanocombinations can be utilized to improve cancer nanotherapy by induction of apoptosis in vitro. Analysis at the molecular level revealed that the Qtn-PVPylated-TiO2NPs nanocombinations induced Δψm-mediated apoptotic signaling pathways. Overall, this study demonstrated that careful design of non-toxic nanocarriers for cancer nanotherapy can yield affordable NDDS.

Correction: Mitochondrial dysfunction-induced apoptosis in breast carcinoma cells through a pH-dependent intracellular quercetin NDDS of PVPylated-TiO2NPs.

Correction for 'Mitochondrial dysfunction-induced apoptosis in breast carcinoma cells through a pH-dependent intracellular quercetin NDDS of PVPylated-TiO2NPs' by Thondhi Ponraj et al., J. Mater. Chem. B, 2018, 6, 3555-3570.