Ficus racemosa Stem Bark Extract: A Potent Antioxidant and a Probable Natural Radioprotector

Ethanol extract (FRE) and water extract (FRW) of Ficus racemosa (family: Moraceae) were subjected to free radical scavenging both by steady state and time resolved methods such as nanosecond pulse radiolysis and stopped-flow spectrophotometric analyses. FRE exhibited significantly higher steady state antioxidant activity than FRW. FRE exhibited concentration dependent DPPH, ABTS•−, hydroxyl radical and superoxide radical scavenging and inhibition of lipid peroxidation with IC50 comparable with tested standard compounds. In vitro radioprotective potential of FRE was studied using micronucleus assay in irradiated Chinese hamster lung fibroblast cells (V79). Pretreatment with different doses of FRE 1h prior to 2 Gy γ-radiation resulted in a significant (P < 0.001) decrease in the percentage of micronucleated binuclear V79 cells. Maximum radioprotection was observed at 20 μg/ml of FRE. The radioprotection was found to be significant (P < 0.01) when cells were treated with optimum dose of FRE (20 μg/ml) 1 h prior to 0.5, 1, 2, 3 and 4 Gy γ-irradiation compared to the respective radiation controls. The cytokinesis-block proliferative index indicated that FRE does not alter radiation induced cell cycle delay. Based on all these results we conclude that the ethanol extract of F. racemosa acts as a potent antioxidant and a probable radioprotector

Preparation and electrical characterization of electrospun multi wall carbon nano tube embedded conductive Su8 nanofibers

This paper reports preparation of conductive SU-8 derived nanofibers using electrospinning technique. Nanofibers derived out of SU-8, a negative epoxy photoresist are insulating in nature. In order to increase the conductivity, multi walled carbon nanotubes (MWCNTs) are embedded into the nanofibres. This is achieved by mixing MWCNTs dispersed in chloroform with SU-8 negative photoresist. The mixture is then electospun onto array of copper (Cu) electrodes. The conductivity is further improved by a low temperature heat treatment process. This paper reports in detail, the steps involved in fabrication and electrical characterization of these MWCNTs embedded SU-8 nanofibres. Index Terms: SU-8, Multi walled Carbon Nanotube Elctrospinning, Heat treatment, Electrical Conductivity Electrospinning technique as a simple, convenient, and versatile method has been utilized in the preparation of many one-dimensional nanostructural materials such as long fibers with diameters ranging from tens of nanometers up to micrometers. Nanofibers can be produced with a variety of polymers depending on the application. In recent years, carbon-based nanostructures, such as carbon nanotubes (CNTs), nanofibers, and graphene as well as various inorganic nanowires have shown great potential for developing biosensors with improved sensitivity. SU-8 is a negative epoxy photoresist which is biocompatible and its surface can be easily functionalized. Nanofibers derived out of SU-8 can potentially be used as high sensitive biosensors. The resistivity of SU-8 is really high which causes the nanofibers derived out of it to be highly resistive. Researchers have employed pyrolysis technique to carbonize SU-8 which results in enhanced conductivity. These high temperature processes hinder integrating the nanofibers in various other technological domains, specifically CMOS compatible biosensor application which our group is targeting to achieve. Alternatively conductivity can be enhanced by embedding nanofibers with MWCNTs. To the best of our knowledge, there is no report on enhancement of conductivity of SU-8 derived nanofibers using MWCNTs. This paper addresses the challenges involved in preparing these nanofibres. II. Experimental Details III. Results and Discussion IV. Conclusions References FIG.1: Schematic representing fabrication of micro-electrode array using lift off process This work reports the methodology to prepare MWCNTs embedded SU-8 derived nanofibers. A significant improvement in electrical conductivity is achieved using a low heat treatment process. These nanofibers can potentially be used in impedance based or ISFET based biosensors by performing suitable surface functionalization based on the target analyte. Abstract IWPSD 201