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Vadekeetil A.,Panjab University | Alexandar V.,Chettinad Academy of Research and Education CARE | Chhibber S.,Panjab University | Harjai K.,Panjab University
Microbial Pathogenesis

Quorum sensing inhibitors (QSIs) act as antivirulent agents since quorum sensing (QS) plays a vital role in regulating pathogenesis of Pseudomonas aeruginosa. However, application of single QSI may not be effective as pathogen is vulnerable to successful mutations. In such conditions, combination of QSIs can be exploited as there can be synergistic or adjuvant action. In the present study, we evaluated the antivirulence efficacy of combination of Vaccinium macrocarpon proanthocyanidin active fraction (PAF) and ciprofloxacin (CIP) at their sub-MICs using standard methods followed by analysis of their mode of action on QS using TLC and molecular docking. There was significant improvement in action of CIP when it was combined with PAF in reducing the QS controlled virulence factors (p < 0.05), motilities and biofilm of P. aeruginosa. TLC profiles of QS signals [(Acyl homoserine lactone (AHL) and Pseudomonas quinolone signal (PQS)] indicated that CIP in combination with PAF, besides showing inhibitory action on production of AHLs, also modulated production and inactivation of PQS. Docking scores also supported the observation. We therefore hypothesize that PAF-CIP combination, having improved anti-virulence property; can be exploited as a potent drug pairing against P. aeruginosa. © 2015 Elsevier Ltd. Source

Poornima V.,CSIR - Central Leather Research Institute | Alexandar V.,Chettinad Academy of Research and Education CARE | Iswariya S.,CSIR - Central Leather Research Institute | Perumal P.T.,CSIR - Central Leather Research Institute | Uma T.S.,CSIR - Central Leather Research Institute
RSC Advances

This review highlights the impact of heavy-metal contamination on the human population and the need for its detection. Minute amounts of mercury ions present in a soluble form in water enter the life cycle of man and produce an impact to an extent that can even affect the foetus inside the womb. Therefore, detection of heavy-metal contamination in water sources is essential. This review proposes the development of simple gold nanoparticle-based sensors for the visual detection of mercury. Gold nanoparticles that have been modified using various functional units are employed in the detection of Hg2+ contamination. Simple, colorimetric methods have been employed in the detection and the major advantage of these sensors is that they are not only simple but also very effective. As the presence/absence of Hg2+ contamination can be detected using the naked eye, these sensors are furthermore user-friendly and, above all, very cheap when compared to other methods that employ the use of highly sophisticated and costly instruments. © The Royal Society of Chemistry 2016. Source

Haribabu V.,Chettinad Academy of Research and Education CARE | Farook A.S.,Chettinad Hospital and Research Institute CHRI | Goswami N.,Geological Survey of India | Murugesan R.,Chettinad Academy of Research and Education CARE | Girigoswami A.,Chettinad Academy of Research and Education CARE
Journal of Biomedical Materials Research - Part B Applied Biomaterials

Magnetic resonance imaging has acquired importance as a major tool for diagnosis and staging of cancers in humans. Injection of certain imaging agents have proved to improve contrast between normal and cancer cells on magnetic resonance imaging (MRI). Using the principles of MR contrast imaging, we have designed a dual mode (T1 and T2) contrast agent based on folic acid functionalized manganese ferrite nanoparticles (MNP) entrapped in 3G polyamidoamide (PAMAM) dendrimers. The ratio of Mn:Fe was tuned to achieve optimal performance. This multifunctional nanocarrier system was developed for targeting cancer cells to produce both T1 and T2 contrast which in turn helps in better diagnosis and staging of cancer. FTIR spectroscopy, X-Ray diffraction, atomic absorption spectroscopy, UV-Visible spectroscopy, and dynamic light scattering measurements were employed to characterize the multifunctional system at different stages of engineering. The ratio of relaxivities r2/r1 is 4.6 at 1.5 T for the MNP prepared with 0.5 molar ratio of Mn/Fe based on MR images obtained from phantom and tumor bearing mouse. The value of r2/r1 shows that the 0.5 molar ratio of Mn/Fe can be used to prepare MNP for the production of dual mode contrast in MR imaging. © 2015 Wiley Periodicals, Inc. Source

Girigoswami K.,Chettinad Academy of Research and Education CARE | Viswanathan M.,Chettinad Academy of Research and Education CARE | Murugesan R.,Chettinad Academy of Research and Education CARE | Girigoswami A.,Chettinad Academy of Research and Education CARE
Materials Science and Engineering C

Abstract Zinc oxide (ZnO) is explicitly used in sunscreens and cosmetic products; however, its effect in vivo is toxic in some cases. The UV blocking efficacy of ZnO nanoparticles is lost due to photocatalysis. To isolate a lower toxic species of sunblockers, ZnO nanoparticles were synthesized and coated with chitosan - a natural polymer (ZnO-CTS) and polyethylene glycol (PEG) - a synthetic polymer (ZnO-PEG). Coating with CTS and PEG circumvented the photocatalytic activity, increased the stability and improved the UV absorption efficacy. The effect of ZnO, ZnO-CTS and ZnO-PEG nanoparticles in vivo on zebrafish embryo revealed lower deposition of ZnO-CTS and ZnO-PEG nanoparticles atop the eggs compared to ZnO. The survival of zebrafish embryos was always found to be higher in case of ZnO-CTS with respect to ZnO-treated ones. PEG coating exhibited better UV attenuation, but, in vivo it induced delayed hatching. Thus, one of the reasons for better survival could be attributed to lower aggregation of ZnO-CTS nanoparticles atop eggs thereby facilitating the breathing of embryos. © 2015 Elsevier B.V. Source

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