RESUMO
For various industrial processes, the stabilization of an oil phase is crucial and demands a proper balance of complex interactions in an emulsion system. In Pickering emulsions, this is achieved by introducing nanoparticles, which become organized at the oil-water interface. The influence of interparticle interactions towards the formation of a stable emulsion and the ordering of the stabilizing nanoparticles is intriguing and needs attention. In this work, the role of amphiphilic interactions between hydrophilic silica nanoparticles and the Pluronic F127 tri-block co-polymer towards the spontaneous formation of a fairly stable Pickering emulsion has been studied using small-angle X-ray scattering. Unlike the usual random arrangements of the nanoparticles in a conventional Pickering emulsion, we observed highly organized silica nanoparticles at the oil-water interface. The established standard raspberry structural model of the Pickering emulsion fails to explain such strong ordering as observed in the present case. A plausible formation mechanism of the present Pickering emulsion with a high on-surface silica correlation is elucidated on the basis of the combined interactions of the block co-polymer and silica particles. A computer model is developed to elucidate the effects of size and distribution of the surface-decorating nanoparticles and their positional correlation.
RESUMO
To explore possible applications of iodoacetate (IA), a glycolytic inhibitor, in cancer treatment, we screened its cytotoxicity and radioprotective/sensitizing efficacy in three different mammalian cell lines; A549 (human lung carcinoma), MCF7 (human mammary cancer), a non-cancerous CHO (Chinese hamster ovary) cells and human lymphocytes. Experiments were carried out using IA concentrations ranging from 0.01 to 2.5 µg/ml, with or without 60Coγ-radiation. In the outcomes, IA was found to exhibit higher toxicity in the cancer cells, whereas it was non-toxic/marginally toxic to the non-cancerous cells. Considerably higher glucose uptake in both cancer cells lines was observed indicating higher rates of glycolysis. IA significantly inhibited glycolysis as reflected by GAPDH activity inhibition. Radiomodifying effects of IA were found to be concentration dependent in both cancerous and non-cancerous cells. The response in non-cancerous was found to be biphasic: at lower concentrations, it offered significant radioprotection; however, the protection decreased with increasing concentration. Moreover, at the highest tested concentration, marginal radiosensitization was also observed (as indicated by clonogenic assay). In both cancer cells, IA offered significant amount of radiosensitization which was considerably high at higher concentrations. Further experiments were carried out to estimate the Dose Modification Factor (DMF) to quantify and compare relative radiosensitization by IA in cancer and normal cell lines. The DMF was calculated for three different concentrations of IA, 0.5, 1, and 1.5 µg/ml, and corresponding values were found to be 1.26, 1.43, and 1.89 for A549 cancer cells, whereas for normal CHO cells, it was 1.13, 1.13, and 1.24. In conclusion, differential killing and radiosensitizing effects of IA suggest that it may have potential use as a anticancer agent and radiosensitizer in cancer therapy.
Assuntos
Iodoacetatos/farmacologia , Radiossensibilizantes/farmacologia , Animais , Transporte Biológico/efeitos dos fármacos , Transporte Biológico/efeitos da radiação , Células CHO , Morte Celular/efeitos dos fármacos , Morte Celular/efeitos da radiação , Linhagem Celular Tumoral , Cricetinae , Cricetulus , Relação Dose-Resposta a Droga , Glucose/metabolismo , Humanos , Linfócitos/efeitos dos fármacos , Linfócitos/metabolismo , Linfócitos/efeitos da radiaçãoRESUMO
Current protocols for storage of white blood cells (WBCs) rely on constant refrigeration. The protocol described below explains the preparation of a fixative combination saline (FCS) formulation, which allows fixation of human WBCs and lysis of red blood cells and platelets (at ambient temperature, 4-35oC) in whole blood samples in one step. FCS can be used for storing and transporting blood at ambient temperatures for up to 4 months, without altering the nuclear morphology and genomic integrity of WBCs.