@article {45497, title = {Flexible and free-standing reduced graphene oxide thick films with PMMA stabilized silver nanoparticles, as a potential probe for cancer thermal therapy}, journal = {Biomedical physics and engineering express}, volume = {4}, year = {2018}, month = {OCT }, pages = {65032}, type = {Article }, abstract = {hermal therapy is an efficient, cost-effective method for treating different types of cancers and hence flexible, light weight, biocompatible heating materials with low power consumption are of utmost importance. Partially reduced flexible, robust and bio-compatible thick graphene oxide films with, mostly edge functionalized Polymethyl methacrylate (PMMA) and in situ grown silver nanoparticles were prepared using simple soak and dry strategy. Larger distribution of silver nanoparticles with a mean diameter of 2.5 nm were anchored towards the edges of these thick films. The electrothermal (Joule heating) performance were found to increase in the presence of silver nanoparticles due to decrease in sheet resistance (0.33 {\texttimes} 104 Ωm) and increase in electron-phonon interaction. These free-standing, flexible films exhibited stable Joule heating behavior under repeated voltage on/off cycles. In-vitro studies performed on breast cancer cells in the presence of the prepared films, with an external applied voltage of 10 VDC, shows 67\% cell death. This work proves the potentiality of thick heterogeneous (partially) reduced graphene oxide films towards site specific destruction of solid tumors by utilizing its Joule heating properties.}, doi = {10.1088/2057-1976/aae90c}, author = {Asha, S. and Nimrodh Ananth, A. and Jose, S. P. and Rajan, M. A. J.} } @conference {44549, title = {Polyethyleneglycol/silver functionalized Reduced graphene oxide aerogel for environmental application}, booktitle = {62nd Dae Solid State Physics Symposium}, year = {2018}, publisher = {Dept Atom Energy; Board Res Nucl Sci, Dept Atom Energy; Bhabha Atom Res Ctr}, organization = {Dept Atom Energy; Board Res Nucl Sci, Dept Atom Energy; Bhabha Atom Res Ctr}, address = {2 Huntington Quadrangle, Ste 1 No1, Melville, NY 11747-4501 USA}, abstract = {

Polyethylene glycol (PEG)/Silver (Ag) functionalized reduced graphene oxide aerogel (RGOA) was synthesized. PEG/Ag decorated reduced graphene oxide aerogel was characterized using XRD, Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR). The surface morphology of PEG/Ag/RGOA was analyzed using scanning electron microscope. The non-covalent interaction between reduced graphene oxide layers and the interaction between PEG and Ag on RGOA were studied by FT-IR spectra. It was observed that the interaction between Ag and PEG could enhance the properties of RGOA. Methyl Orange (MO) dye degradation was observed from UV-Vis Spectra. The process was studied by monitoring the simultaneous decrease in the height of UV-Vis absorption peak of dye solution. The results show that PEG/RGOA and PEG/Ag/RGOA are an efficient catalyst for dye degradation.

}, isbn = {978-0-7354-1634-5}, doi = {10.1063/1.5028718}, author = {Kumari, G. Vanitha and Asha, S. and Ananth, A. Nimrodh and Rajan, M. A. Jothi and Mathavan, T.} } @article {44529, title = {Surface colonized silver nano particles over chitosan poly-electrolyte micro-spheres and their multi-functional behavior}, journal = {Materials Research Express}, volume = {5}, year = {2018}, month = {FEB }, pages = { 025032}, type = {Journal Article}, abstract = {hitosan/tripolyphosphate polyelectrolyte (TPP) microspheres, decorated and surface functionalized with silver nanoparticles (NPs) of average diameter of 15 nm, were synthesized following a simple two-step procedure. These Ag NP-functionalized polyelectrolyte microspheres (Ag-CSPMs) are found to be biocompatible and enhancing the reactive oxygen species in curcumin with excellent anti-bacterial activity for selected Gram-positive and negative bacterial strains, making them much attractive relative to bare surface counterparts; the well-stabilized silver NPs do not form any agglomerations on the surface of the chitosan microspheres. They also show excellent cytotoxic behavior towards MCF7 cell lines, showing a half-maximal inhibitory concentration (IC50) of 32 μg ml-1. Therefore, Ag-CSPMs exhibit multi-functional ability having potential towards theranostics applications.}, keywords = {antibacterial properties, Chitosan, Cytotoxicity, reactive oxygen species, silver nanoparticles, theranostics}, issn = {20531591}, doi = { 10.1088/2053-1591/aaa3c6}, author = {Prakash, B.}, editor = {Asha, S.} } @article {44484, title = {Temperature dependent electron transport behavior of poly (methyl methacrylate)/silver functionalized reduced graphene oxide films}, journal = {AIP Conference Proceedings}, volume = {1942}, year = {2018}, month = {APR }, type = {Journal Article}, abstract = {

Poly (methyl methacrylate) (PMMA) and silver functionalized reduced graphene oxide film were prepared and were investigated using FTIR and Raman. Electron transport behavior of these samples, at low temperature were studied. The prepared film exhibited a temperature dependent electron transport, at higher temperatures Arrhenius-like temperature dependence of resistance was observed indicating band like electron transport with a small thermal activation energy. At further lower temperatures hopping mechanism of conduction was observed due to the presence of defects. The conduction due to band-like electron transport at higher temperature is attributed to the easier excitation of charge carriers to the conduction band, whereas at lower temperatures conduction occurs through hopping mechanism due to localized states around Fermi level in the presence of defects.

}, issn = {0094243X}, doi = {10.1063/1.5029028}, author = {Asha, S.}, editor = {Ananth, A. Nimrodh} } @article {46980, title = {Temperature assisted reorganization of silver nanoparticles in free-standing, flexible chitosan functionalized reduced graphene oxide thick films: A potential SERS probe for folic acid sensing}, journal = {Materials Science and Engineering B-Advanced Functional Solid-State Materials}, volume = {252}, year = {2020}, month = {FEB}, pages = {114454}, type = {Article}, abstract = {

Chitosan and silver functionalized free standing reduced graphene oxide (rGO) films were prepared using simple soak and dry strategy. Redistribution of silver aggregates on chitosan functionalized rGO films were observed by thermally annealing these films at 450 degrees C, in an inert atmosphere. The re-organization / redistribution of silver aggregates in the rGO films were studied using in-situ Raman scattering signals. The redistribution of silver particles occurs through melting of micron sized silver aggregates during annealing. The rearrangement of the micro-sized silver aggregates to spherical silver nanoparticle on chitosan functionalized rGO film, as a result of temperature was assisted through factors such as graphene surface ripple rearrangement and the denaturation of rGO surface interacting chitosan chains. These free-standing films with redistributed silver nanoparticles showed excellent surface enhanced Raman scattering (SERS) effect with enhanced Raman signals for folic acid sensing, showcasing its potentiality to be utilized as flexible SERS based sensors.

}, keywords = {Free-standing, graphene oxide, sensing, SERS, silver nanoparticles, Thick-films}, issn = {0921-5107}, doi = {10.1016/j.mseb.2019.114454}, author = {Asha, S. and Ananth, A. Nimrodh and Jose, Sujin P. and Rajan, Michael Anjello Jothi} }