Curcumin Nanocapsules based on carbon dots for photodynamic sterilization towards Listeria monocytogenes and Staphylococcus aureus.

Curcumin (Cur) as a natural food additive and photosensitizer has been widely applied on photodynamic sterilization and preservation for food, but the poor aqueous solubility and light stability restrict its extensive application. In this study, we report a Cur nanocapsules (Cur-CDs) made by carbon dots (CDs). Attributing to the hydrogen bonds formed between Cur and CDs, Cur-CDs exhibits excellent Cur aqueous solubility each to 9286.98 ng/mL (enhanced by 246.27 times) and light stability (enhanced by 1.51 times). The photogenerated electron transmission from Cur to CDs in addition resulted in >1.23 and 1.60 times generation of •O2- and •OH, compared to that of bare Cur. Accordingly, 5.73 × 103 CFU L. monocytogenes, and 5.43 × 103 CFU S. aureus were killed by 0.06 mg/mL Cur-CDs within 20 mins of blue light, showing the promising potential in the development and application of safe and environmentally friendly non-thermal sterilization technology based on Cur-CDs.

Photocatalytic degradation of Rhodamine B dye by nanostructured powder systems containing nanoencapsulated curcumin or ascorbic acid and ascorbyl palmitate liposomal.

Due to inadequate treatment and incorrect management, wastewater with dyes has a great toxic potential as an environmental liability, representing a major concern. In this context, this work aims to investigate the potential application of nanostructured powdery systems (nanocapsules and liposomes) in the photodegradation of Rhodamine B (RhB) dye, under UV and visible irradiation. Curcumin nanocapsules and liposomes containing ascorbic acid and ascorbyl palmitate were prepared, characterized, and dried using the spray drying technique. The drying processes of the nanocapsule and the liposome showed yields of 88% and 62%, respectively, and, after aqueous resuspension of the dry powders, it was possible to recover the nanocapsule size (140 nm) and liposome size (160 nm). The dry powders were characterized by Fourier transform infrared spectroscopy (FTIR), N2 physisorption at 77 K, X-ray diffraction (XRD), and diffuse reflectance spectroscopy (DRS-UV). Under UV irradiation, 64.8% and 58.48% of RhB were removed with nanocapsules and liposomes, respectively. While under visible radiation, nanocapsules and liposomes were able to degrade 59.54% and 48.79% of RhB, respectively. Under the same conditions, commercial TiO2 showed degradation of 50.02% (UV) and 42.14% (visible). After 5 cycles of reuse, there was a decrease of about 5% for dry powders under UV irradiation and 7.5% under visible irradiation. Therefore, the nanostructured systems developed have potential application in heterogeneous photocatalysis for the degradation of organic pollutants, such as RhB, as they demonstrated superior photocatalytic performance to commercial catalysts (nanoencapsulated curcumin > ascorbic acid and ascorbyl palmitate liposomal > TiO2).

Curcumin nanocapsules effect in apoptotic processes, gene expression, and cell cycle on Hep-G2 cell lines.

OBJECTIVES: Curcumin has antioxidant and antiproliferative properties, and its therapeutic effect must be considered. Nanocurcumin capsules showed a potential increase against in vitro biological cancer. This study sought to determine how curcumin nanoparticles and nanocapsules affected the expression of p53, Bcl-2, Bax, and Bax in a liver cancer cell line (Hep-G2). Mechanisms of apoptosis were also examined in this cell line. METHODS: This study used quantitative real-time polymerase chain reaction (qRT-PCR) to analyze the p53, Bcl-2, Bax, and Caspase-3 gene pathways and to evaluate the molecular mechanisms responsible for the efficacy of curcumin nanoparticles (CNPs) and curcumin nanocapsules (CNCs) against liver cell lines. Flow cytometry was used to check for signs of apoptosis and the cell cycle. RESULTS: Curcumin nanocapsules produced by the ball milling process at 90 min significantly boosted the populations of apoptotic cells in a dose- and time-dependent manner. The mRNA expression analysis revealed that the proapoptotic Bax, Caspase-3, and the tumor suppressor gene p53 were upregulated throughout the process started by curcumin nanocapsules and decreased in the Bcl-2/Bax ratio. CONCLUSION: This research provides a fresh understanding of the molecular mechanisms behind the liver cancer-fighting abilities of curcumin nanoparticles. Curcumin nanocapsules produced through a unique mechanical technique can be used as an anticancer agent.