Studies were undertaken to examine the mechanism of mediation of silver nanoparticles in inhibiting biofilm formation by Pseudomonas aeruginosa through LuxI/LuxR system of signal transduction. This study includes the basic signaling transduction mechanism LasR, QscR, RhlR, and Vfr signaling model systems. The arbitrary homology models built with the I-TASSER server were evaluated and validated with the Qmean web server. Based on the Z-score and the relative square mean distance (RMSD) values, the structures were validated. The interaction results of the nanoparticle with the rigid docking proved the requirement of minimal energy for the inhibition of the protein active site by the silver nanoparticle. This principle docking experiment suggests that the biofilm formation in Gram-negative bacteria can be inhibited by the silver nanoparticles at the signal transduction level. Graphical abstract Systematic outline of present study; Stage one provides the data sampling and generation of pdb systems to conform the structure of bacterial signal sytems like LasR/LasI; RhlR/RhrI; QscR/QscI; VfrR/VfrI. Stage two involves docking of silver nanoparticles with Bacterial signal protein strucutres which are listed in Stage one. The Final Stage involves in understanding the development of appropriate mechanism behind the biofilm inhibition by silver nanoparticles.

No abstract

Cancer cell heterogeneity (CCH) is crucial in understanding cancer progression and metastasis. The CCH is one of the stumbling blocks in modern medicine's therapeutics and diagnostics . An in-vitro model of co-culture systems of MCF-7, HeLa, HEK-293, with THP-1 cells showed the occurrence of EpCAM positive (EpCAM+) and EpCAM negative (EpCAM−) heterogenetic cancer cell types labeled with the Quantum Dot antibody conjugates (QDAb). This in-vitro model study could provide insights into the role of rare cancer cells manifestation and their heterogeneity in metastatic progression and risk for severe infections in these patients. We successfully report the presence of CCH based on the fluorescence ratios of the co-cultured cancer cells when treated with the QDAb. These short-term mimic co-cultures give a compelling and quite associated model for assessing early treatment responses in various cancers.

Quantum dots (QD) with chemical composition QD 650CdSe=ZnS_Ni were successfully synthesized using a hydrothermal method and chemical precipitation. The nanocrystalline phase of the nanostructures was isolated and characterized using X-ray diffraction (XRD). The mean crystalline size doped core/shell Ni-dopant range was 9.0 ± 2.0 nm. The ferromagnetic data revealed the magnetic behaviour of QD 650CdSe=ZnS_Ni . The optical absorption measurements of these QDs were in the UV-visible light range 200-800 nm for a band gap value of 2.11 eV for QD 650 CdSe=ZnS_Ni . This means that pure QD 650CdSe and QD 650 CdSe=ZnS_Ni underwent a redshift when compared with bulk CdSe. For QD 650CdSe=ZnS_Ni there was successful uptake by cell lines including HeLa and MCF-7 for bioimaging and sorting applications.