Iron Oxide-Doped Carbon Nanoparticles Stabilised with Functionally Modified Hyperbranched Polyglycerol for Cd2+ Sensing and Photodynamic Antibacterial Therapeutic Applications.

Nanoscale materials are being developed from individual particles to multi-component assemblies, with carbon nanomaterials being particularly useful in bioimaging, sensing, and optoelectronics due to their unique optical properties, enhanced by surface passivation and chemical doping. Noble metals are commonly used in conjunction with carbon-based nanomaterials for the synthesis of nanohybrids. Carbon-based materials can function as photosensitizers and effective carriers in photodynamic therapy, enabling the use of combined treatment approaches. The hydrophobicity and agglomeration tendency of carbon nanoparticles pose a drawback. This study is an attempt to overcome these limitations, which involved the synthesis of iron oxide-doped carbon nanoparticles through the carbonisation of citric acid and hexamethylene tetramine, followed by doping them with iron oxide. The as synthesized iron oxide-doped carbon nanoparticles were stabilised with fluorescently modified hyperbranched polyglycerol. The efficacy of these nanoparticles in photodynamic antibacterial therapy and Cd (II) ion sensing was investigated. The selectivity of stabilised nanoparticles against Cd2+ ion is presented in the current study. The current study also compares the antibacterial efficacy of undoped, iron oxide-doped and stabilised nanoparticle systems. The possible toxic effects of the synthesised nanosystems were investigated in order to assess their suitability for biomedical applications and establish their safety profile.

Biochemical basis for functional ingredient design from fruits.

Functional food ingredients (nutraceuticals) in fruits range from small molecular components, such as the secondary plant products, to macromolecular entities, e.g., pectin and cellulose, that provide several health benefits. In fruits, the most visible functional ingredients are the color components anthocyanins and carotenoids. In addition, several other secondary plant products, including terpenes, show health beneficial activities. A common feature of several functional ingredients is their antioxidant function. For example, reactive oxygen species (ROS) can be oxidized and stabilized by flavonoid components, and the flavonoid radical can undergo electron rearrangement stabilizing the flavonoid radical. Compounds that possess an orthodihydroxy or quinone structure can interact with cellular proteins in the Keap1/Nrf2/ARE pathway to activate the gene transcription of antioxidant enzymes. Carotenoids and flavonoids can also exert their action by modulating the signal transduction and gene expression within the cell. Recent results suggest that these activities are primarily responsible for the health benefits associated with the consumption of fruits and vegetables.

Physico-chemical characteristics of nanovesicle-carbohydrate complexes in grape juice concentrate.

It is generally assumed that polyphenols, such as anthocyanins in fruit juice, exist in a free soluble state and are readily available for absorption in the gastro-intestinal tract. In the present study, we have investigated the interaction of polyphenols with soluble carbohydrate polymers, such as pectin and lipid nanovesicles, that are generated during homogenization of the fruit tissue during juice extraction. A commercially available grape juice concentrate contained nearly 25% of polyphenol fraction bound to macromolecules that were nondialyzable. Treatment of dialyzed juice with cellulase, pectinase, and beta-galactosidase did not cause the release of bound polyphenols; however, treatment with triton X-100 caused an increased release of bound polyphenols. The dialyzate contained relatively more -3-O glucosides and -3-O-acetoyl glucosides in comparison to the bound fraction which was enriched in -3-O-coumaroyl glucosides, suggesting qualitative differences in the bound and the free anthocyanin composition. Electron microscopic analysis of the juice fractions revealed the presence of electron-dense nanovesicle-fiber complexes ranging from 10 to 200 nm in diameter. Such complexes were absent in the dialyzate fraction. Cellulase treatment did not change the morphology of the complexes; however, treatment with pectinase and beta-galactosidase disrupted the complexes, releasing vesicular structures, suggestive of the pectin nature of the fibrous matrix. The dialyzed and the dialyzate fractions also showed differences in their 1H NMR and fluorescence spectral characteristics. The dialyzed fraction containing polyphenol-pectin complexes showed no superoxide scavenging capacity, reduced hydroxyl radical scavenging activity, and high 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity, indicating potential changes in functionality because of the complex formation.