Nanoparticles of methylene blue enhance photodynamic therapy.

Breast cancer is the most commonly diagnosed cancer and the second leading cause of death related to cancer among women worldwide. Screening and advancements in treatment have improved survival rate of women suffering from this ailment. Novel therapeutic techniques may further reduce cancer related mortality. One of several emerging therapeutic options is Photodynamic Therapy (PDT) that uses light activated photosensitizer (PS) inducing cell death by apoptosis and/or necrosis. Nanotechnology has made contribution to improve photosensitizer for PDT, increasing the efficiency of therapy using gold and silver nanoparticles. Efforts have been done to develop better mechanism to improve PS and consequently PDT effects. In this study, we investigate the efficacy of the PDT using gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs) when mixed to methylene blue (MB) in the treatment of the human breast adenocarcinoma cell line (MDA-MB-468). The MDA-MB-468 was treated in the presence of different MB concentrations with/without AuNPs or AgNPs. The colloidal solution of AgNPs showed a plasmon resonance band at 411 nm in UV-visible range and a bimodal size distribution. The results of viability analysis showed that cells treated with nanoparticles exhibited higher cytotoxicity than cells treated with only MB, improving the efficiency of the treatment in the tumor cells. The cytotoxicity effect of MB associated with AgNPs on MDA-MB-468 cell line could be related to increased reactive oxygen species production due to the release of Ag+ ions from nanoparticles surface, suggesting that the association between FS and AgNPs has potential as a PDT agent.

FTIR study of secondary structure changes in Epidermal Growth Factor by gold nanoparticle conjugation.

Conformation of protein is vital to its function, but may get affected when processing to manufacture products. It is therefore important to understand structural changes during each step of production. In this study, we investigate secondary structure changes in the targeting protein Epidermal Growth Factor (EGF) during synthesis of theranostic bifunctional nanoparticle, devised for Photodynamic therapy of breast cancer. We acquired FTIR spectra of EGF; unconjugated, post treatment with α-lipoic acid, attached to gold nanoparticle, and bound to the bifunctional nanoprobe. We observed decreasing disordered structures and turns, and increasing loops, as the synthesis process progressed. There was an overall increase in ß-sheets in final product compared to pure EGF, but this increase was not linear and fluctuated. Previous crystal structure studies on EGF-EGFR complex have shown loops and ß-sheets to be important in the binding interaction. Since our study found increase in these structures in the final product, no adverse effect on binding function of EGF was expected. This was confirmed by functional assays. Such studies may help modify synthesis procedures, and thus secondary structures of proteins, enabling increased functionality and optimum results.

Salivary Cortisol Responses and Session Ratings of Perceived Exertion to a Rugby Match and Fatigue Test.

This study compared the effects of an official rugby match and a fatigue test on the salivary cortisol responses of 13 rugby players. We also examined the relationship between this cortisol response and session ratings of perceived exertion (session-RPE). We collected saliva before and after the match and fatigue test and assessed physical effort intensity via session-RPE using a CR-10 scale. We measured cortisol concentration by enzyme-linked immunosorbent assays. Results were greater session-RPE and cortisol concentrations for the rugby match, compared with the fatigue test. There was a significant difference between cortisol concentrations obtained pre- and postmatch ( p < .022) and significant correlations between cortisol response and session-RPE sampling in both the rugby match ( r = .81; p < .001) and fatigue test ( r = .91; p < .001). This study provides evidence of greater perceived effort and higher cortisol concentrations in actual competition versus a fatigue test. Our data further support session-RPE as a relatively inexpensive close correlate of a stress biomarker (cortisol response). Thus, session-RPE can be used by coaches as a valid indication of training loads and adequate recovery time after exertion.

Synthesis and characterization of gold nanostructured Chorin e6 for Photodynamic Therapy.

Photodynamic therapy is an alternative treatment for cancer based on cellular uptake of a photosensitizer, illuminated with an appropriate wavelength in the presence of oxygen. A cascade of reactions generates reactive oxygen species leading to cell death. Using carbodiimide chemistry, chlorin e6 (Ce6) was covalently bonded to thiourea, and (via the sulphur end group) to gold nanoparticles (AuNPs), forming the Ce6-AuNP complex. Ce6 absorbs in the range 650-680nm, where the coefficient of biological tissue absorption is low (part of the therapeutic window), which is ideal for biological application. Transmission Electron Microscopy, UV-vis spectroscopy, Fourier transform Infrared Spectroscopy and Zeta potential measurements were completed to characterize the Ce6-AuNP complex. The bare AuNPs have an average diameter of 18±4nm. A line of human breast carcinoma cells (MDA-MB-468) was used to determine whether Ce6 functionalization to AuNPs potentiate its activity. Trypan blue assays were used to assess cell viability. In the absence of light, Ce6 either alone or bounded to AuNPs was not cytotoxic. When irradiated at 660nm, the cytotoxicity of Ce6-AuNP was higher than Ce6 alone for MDA-MB-468 cells using 4h incubation. AuNPs without Ce6 showed no cytotoxic.