Biological Synthesis of CdTe Quantum Dots and Their Anti-Proliferative Assessment Against Prostate Cancer Cell Line.

Quantum dots (QDs) are semiconducting materials which have a wide array of applications starting from semiconducting devices, in humidity and pressure sensors and in medical imaging including cancer therapy. In the present study, cadmium telluride (CdTe) QDs were synthesized by a biological method using yeast cells, Saccharomyces cerevisiae in modified Czapek's medium. QDs were characterized by transmission electron microscopy and X-ray diffraction. Cancer cells were treated with 2, 4, 8 and 16 µM concentrations of CdTe QDs for 24 h. The anti-proliferative activity was determined by using MTT assay, by evaluating the production of reactive oxygen species (ROS), and also by nuclear apoptosis and cell cycle analysis using a flow cytometer against human prostate carcinoma cell line PC-3. The size of the CdTe QDs was approximately 2 nm. In vitro anti-proliferative study showed that CdTe QDs induced cell death and nuclear apoptosis in a dosedependent manner. CdTe QDs induced significant increase in ROS level in PC-3 cells which was dose-dependent. Moreover, CdTe also arrested growth of PC-3 cells in the G2/M phase of the cell cycle. This study elucidates the apoptotic activity of CdTe QDs on prostate carcinoma which could provide useful insights to researchers for its clinical application.

Enhancing using glucose encapsulation, the efficacy of CdO NPs against multi-drug resistant Escherichia coli.

In this study, monodispersed, highly biocompatible and substantially stable glucose encapsulated CdO nanoparticles (G-CdO NPs) of uniform sizes were synthesized using a sol-gel route. In addition, naked CdO (n-CdO) NPs without any capping or surface functionalization were synthesized using the same method. These NPs were uniformly dispersed in an aqueous solution. The synthesis of G-CdO and n-CdO NP was confirmed by UV-Vis spectroscopy, transmission electron microscopy (TEM), zeta potential, and dynamic light scattering analyses. The average size of G-CdO and n-CdO NP was found to be 17±1and 27 ±â€¯1 nm, under TEM, respectively. X-ray diffraction analysis of G-CdO and n-CdO NPs confirmed their sizes to be 18.83 and 28.41 nm, respectively, and revealed their cubic crystal structures with no impurity. The surface functionalization of G-CdO NPs with glucose was confirmed by Nuclear Magnetic Resonance and Fourier-transform infrared spectroscopy analyses. As per our knowledge, this is the first report to investigate the potencies of G-CdO and n-CdO NPs against gram-negative and gram-positive multi-drug resistant (MDR) bacteria. The minimum inhibitory concentrations of G-CdO and n-CdO NPs were6.42 and 16.29 µg/ml, respectively, against Escherichia coli (NCIM 2571-MDR), whereas 7.5 µg/ml & 11.6 µg/ml, respectively against S. aureus (NCIM- 2079) as determined by the double dilution method. The minimum bactericidal concentration was determined at the concentration for which no growth was observed. TEM analysis of E. coli cells treated with G-CdO NPs revealed cell shrinkage and degraded cell membranes, while the cell surfaces of untreated viable cells were smooth.

Chemically synthesized CdSe quantum dots inhibit growth of human lung carcinoma cells via ROS generation.

Quantum dots (QDs), semiconducting materials have potential applications in the field of electronic and biomedical applications including cancer therapy. In present study, cadmium selenide (CdSe) QDs were synthesized by chemical method. Octadecene was used as non-coordinating solvent which facilitated the formation of colloidal solutions of nanoparticles. CdSe QDs were characterized by UV-vis spectrometer and transmission electron microscope (TEM). The size measured by TEM was varied between 2-5 nm depending upon temperature. The cytotoxic activity of QDs was monitored by MTT assay, nuclear condensation, ROS activity and DNA fragmentation assay on human lung epithelial A549 cell line. Cells were treated with different concentrations of varying size of CdSe QDs for 24 h. CdSe QDs induced significant (p < 0.05) dose dependent cytotoxicity and this was comparable to the sizes of particles. Smaller particles were more cytotoxic to the large particles. Fluorescence microscopic analysis revealed that QDs induced oxidative stress generating significant ROS level and consequently, induced nuclear condensation and DNA fragmentation. Study suggested the cytotoxicity of CdSe QDs via ROS generation and DNA fragmentation depending upon particles size.

Pixel entanglement: experimental realization of optically entangled d=3 and d=6 qudits.

We demonstrate a simple experimental method for creating entangled qudits. Using transverse-momentum and position entanglement of photons emitted in spontaneous parametric down-conversion, we show entanglement between discrete regions of space, i.e., pixels. We map each photon onto as many as six pixels, where each pixel represents one level of our qudit state. The method is easily generalizable to create even higher dimensional, entangled states. Thus, the realization of quantum information processing in arbitrarily high dimensions is possible, allowing for greatly increased information capacity.

A theoretical study of the stability of DNA binding with cis/trans platin.

Both cis- and trans-platins are known to form intra- and interstrand cross-linking with DNA. Since the nature and strength of binding is different, it makes their efficacy as anti-tumour drug different. In the present communication, we report theoretical analysis by using an amended Zimm and Bragg theory, to explain the melting behaviour and heat capacity of DNA with and without platin binding. The sharpness of transition has been examined in terms of half width and sensitivity parameter (deltaH/sigma). The experimental measurements of Pilch et al (J Mol Biol 2000, 296, 803) and Ctirad and Brabec (J Biol Chem 2001, 276, 9655) have been used.

Phonon dispersion in polyinosinic acid.

A study of the normal modes of vibration and their dispersion in polyinosinic acid [poly (I)] along the helix axis based on Urey-Bradley force field is reported. It leads to a better interpretation of Raman and FTIR spectra. A comparison of dispersion curves of poly (I) with poly (G) has been made. Characteristic features of dispersion curves, such as regions of high density-of-states, repulsion and character mixing are discussed. Predictive value of heat capacity as a function of temperature is reported.