Nanoparticles of varying composition, size, shape, and architecture have been explored for use as photothermal agents in the field of cancer nanomedicine. Among them, gold nanoparticles provide a simple platform for thermal ablation owing to its biocompatibility in vivo. However, the synthesis of such gold nanoparticles exhibiting suitable properties for photothermal activity involves cumbersome routes using toxic chemicals as capping agents, which can cause concerns in vivo. Herein, gold nanoparticles, synthesized using green chemistry routes possessing near-infrared (NIR) absorbance facilitating photothermal therapy, would be a viable alternative. In this study, anisotropic gold nanoparticles were synthesized using an aqueous route with cocoa extract which served both as a reducing and stabilizing agent. The as-prepared gold nanoparticles were subjected to density gradient centrifugation to maximize its NIR absorption in the wavelength range of 800-1000 nm. The particles also showed good biocompatibility when tested in vitro using A431, MDA-MB231, L929, and NIH-3T3 cell lines up to concentrations of 200 μg/mL. Cell death induced in epidermoid carcinoma A431 cells upon irradiation with a femtosecond laser at 800 nm at a low power density of 6 W/cm(2) proved the suitability of green synthesized NIR absorbing anisotropic gold nanoparticles for photothermal ablation of cancer cells. These gold nanoparticles also showed good X-ray contrast when tested using computed tomography (CT), proving their feasibility for use as a contrast agent as well. This is the first report on green synthesized anisotropic and cytocompatible gold nanoparticles without any capping agents and their suitability for photothermal therapy.

ADAR RNA editing enzymes are high-affinity dsRNA-binding proteins that deaminate adenosines to inosines in pre-mRNA hairpins and also exert editing-independent effects. We generated a Drosophila Adar E374A mutant strain encoding a catalytically inactive Adar with CRISPR/Cas9. We demonstrate that Adar adenosine deamination activity is necessary for normal locomotion and prevents age-dependent neurodegeneration. The catalytically inactive protein, when expressed at a higher than physiological level, can rescue neurodegeneration in Adar mutants, suggesting also editing-independent effects. Furthermore, loss of Adar RNA editing activity leads to innate immune induction, indicating that Drosophila Adar, despite being the homolog of mammalian ADAR2, also has functions similar to mammalian ADAR1. The innate immune induction in fly Adar mutants is suppressed by silencing of Dicer-2, which has a RNA helicase domain similar to MDA5 that senses unedited dsRNAs in mammalian Adar1 mutants. Our work demonstrates that the single Adar enzyme in Drosophila unexpectedly has dual functions.

Targeted biological contrast agents are emerging as promising candidates in the field of cancer theragnostics. Herein, we report an ambient temperature synthesis of a nanosized, antibody functionalized lanthanide doped CaF 2 biolabel and demonstrate in vitro its potential for cancer cell targeting efficacy and specificity. Monodispersed citrate stabilized lanthanide (Eu 3+ ) doped CaF 2 nanoparticles with size ∼25 nm, exhibiting strong fluorescent emission at 612 nm, were prepared using an aqueous wet chemical route at room temperature. Biofunctionalization of the fluorescent nanoparticles using an anti-EGFR antibody through EDC-NHS coupling chemistry enabled targeting of EGFR over-expressing cells. The nanobioconjugates showed preferential binding to EGFR +ve oral epithelial carcinoma cells (KB) and human epidermoid carcinoma cells (A431) with no accumulation onto EGFR −ve non-cancerous NIH 3T3 cells. The fluorescence was maintained after the bioconjugation as well as after attachment to the cancer cells, demonstrating their potential as targeted biolabels. Cytotoxicity evaluation with several cancerous (A431, KB) and non-cancerous (NIH 3T3, L929) cell lines revealed no toxicity at concentrations up to 1 mM. Thus, the fluorescence characteristics and biocompatibility, coupled with the molecular receptor targeting capability, suggest the potential use of CaF 2 in the field of bioimaging.

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