K. Pandian

Ellagic acid encapsulated chitosan nanoparticles for drug delivery system in human oral cancer cell line (KB).

Ellagic acid (EA), a naturally occurring polyphenolic compound is well documented for its anticancer property in numerous pre-clinical models. The properties like poor water solubility and limited oral bio-availability of ellagic acid has hampered its clinical applications. The present study, reports the preparation of ellagic acid encapsulated chitosan nanoparticles (EA@CS-NP) by ionic gelation method as an effective drug delivery for oral cancer treatment. The synthesized ellagic acid nanoparticle is spherical shaped with an average particle size of 176nm. The drug-encapsulation and loading-efficiency of the nanoparticles were 94±1.03% and 33±2.15% respectively. The in vitro drug release profile in the PBS medium shows sustained release of EA from EA@CS-NP. Further, this study evaluates the therapeutic efficacy of EA@CS-NP in human oral cancer cell line (KB) using MTT and DNA fragmentation analysis. EA@CS-NP exhibit significant cytotoxicity in KB cells in a dose-dependent manner with a very low IC50 value compared to the free EA. The results of the present study strengthen our hypothesis and hope that this novel formulation could possibly overcome the current limitations of ellagic acid and can open a new avenue for oral cancer therapy.

Treatment of petroleum refinery wastewater by ultrasound-dispersed nanoscale zero-valent iron particles.

Petroleum refineries release wastewater, which is rich in organic pollutants and cannot be treated easily. This study presents the treatment of petroleum refinery wastewater using nanoscale zero valent iron (NZVI) in the presence of ultrasonication. NZVI characteristics were analyzed using SEM and XRD. The influence of NZVI dosage and initial pH on % chemical oxygen demand (COD) reduction was studied. From the results, it can be inferred that a dosage of 0.15 g/l and an initial pH are optimum for the effective degradation of effluents. The degradation data were found to follow first order kinetics. The results indicate that using NZVI in combination with ultrasonication is an efficient method for the treatment of petroleum refinery wastewater.

Amperometric detection of Sudan I in red chili powder samples using Ag nanoparticles decorated graphene oxide modified glassy carbon electrode.

A simple and sensitive electrochemical method was developed to determine the concentration of Sudan I in chili powder based on silver nanoparticles decorated graphene oxide modified glassy carbon electrode (AgNPs@GO/GCE). The voltammetry behaviour of Sudan I on modified GCE was investigated in phosphate buffer medium (PBS) with various pH ranges and the electron transfer properties were studied. It is found that the AgNPs@GO/GCE can catalyse the reduction of azo group, -N=N- followed by electrochemical oxidation of (-)OH group present in Sudan I dye molecule. Quantitative detection of Sudan I present in food products was carried out by amperometry method in which reduction potential was fixed at -0.77 V vs. Ag/AgCl. The amperometry method showed an excellent performance with a sensitivity of 6.83 μA mM(-1) and a detection limit of 11.4 × 10(-7)ML(-1). A linear calibration graph was constructed in the ranging 3.90 × 10(-6) to 3.19 × 10(-5)ML(-1). The method was successfully applied for the determination of Sudan I in red chili powder samples.

Biopolymers Regulate Silver Nanoparticle under Microwave Irradiation for Effective Antibacterial and Antibiofilm Activities.

In the current study, facile synthesis of carboxymethyl cellulose (CMC) and sodium alginate capped silver nanoparticles (AgNPs) was examined using microwave radiation and aniline as a reducing agent. The biopolymer matrix embedded nanoparticles were synthesized under various experimental conditions using different concentrations of biopolymer (0.5, 1, 1.5, 2%), volumes of reducing agent (50, 100, 150 μL), and duration of heat treatment (30 s to 240 s). The synthesized nanoparticles were analyzed by scanning electron microscopy, UV-Vis spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy for identification of AgNPs synthesis, crystal nature, shape, size, and type of capping action. In addition, the significant antibacterial efficacy and antibiofilm activity of biopolymer capped AgNPs were demonstrated against different bacterial strains, Staphylococcus aureus MTCC 740 and Escherichia coli MTCC 9492. These results confirmed the potential for production of biopolymer capped AgNPs grown under microwave irradiation, which can be used for industrial and biomedical applications.

Targeting and sensing cancer cells with ZnO nanoprobes in vitro

A new class of zinc oxide quantum dots (ZnO QDs) was investigated as nanoprobes for targeting cancer cells in vitro. ZnO nanoparticles were synthesized using conventional sol–gel method and encapsulated using trimethoxy aminopropyl silane. Transferrin, the ligand targeting the cancer cells, was conjugated to the ZnO QDs. In vitro imaging studies using MDA-MB-231 showed the biocompatible ZnO nanoprobe selectively binding to the cell surface receptor and internalizing through receptor-mediated endocytosis. Time-lapsed photobleaching studies indicate the ZnO QDs to be resistant to photobleaching, making them suitable for long term imaging purpose. Investigation of the ZnO nanoprobe as a platform for sensitive bioassays indicates that it can be used as an alternative fluoroprobe for cancer cell targeting and sensing applications.

Sunlight assisted synthesis of silver nanoparticles in zeolite matrix and study of its application on electrochemical detection of dopamine and uric acid in urine samples.

Sunlight assisted reduction of silver ions were accomplished for the synthesis of silver nanoparticles incorporated within the mesoporous silicate framework of zeolite Y. The zeolite-Y and AgNP/Zeo-Y were characterized by field emission scanning electron microscopy, transmission electron microscopy, N2 adsorption-desorption BET isotherm and X-ray diffraction techniques. The incorporation of silver nanoparticles within the porous framework was further confirmed by cyclic voltammetry and electrochemical impedance spectroscopy. An enhanced electrocatalytic oxidation of biologically important molecules like dopamine and uric acid using AgNP/Zeo-Y modified glassy carbon electrode has been developed. A simultaneous oxidation of DA and UA peaks were obtained at +0.31V and +0.43V (vs. Ag/AgCl) using AgNP/Zeo-Y/GCE under the optimum experimental condition. A well-resolved peak potential window (~120mV) for the oxidation of both DA and UA were observed at AgNP/Zeo-Y/GCE system. The calibration curves for DA and UA were obtained within the dynamic linear range of 0.02×10(-6) to 0.18×10(-6)M (R(2)=0.9899) and 0.05×10(-6) to 0.7×10(-6)M (R(2)=0.9996) and the detection limits were found to be 1.6×10(-8)M and 2.51×10(-8)M by using differential pulse voltammetry (DPV) method. The proposed method was successfully applied for the determination of both DA and UA in human urine samples with a related standard deviation was <3%, and n=5 using the standard addition method.

Simultaneous voltammetric determination of vanillin and guaiacol in food products on defect free graphene nanoflakes modified glassy carbon electrode

AbstractSimple and robustic mediator free graphene nanoflake modified glassy carbon electrode (GNF/GCE) was used for the simultaneous determination of vanillin (VAN) and guaiacol (GUA) in food products like chocolate and biscuits by using an amperometric method. Defect-free graphene nanoflakes were obtained by a surfactant assisted exfoliation approach. The resulting graphene flake was characterized by FE-SEM and Raman studies. The electrocatalytic oxidation of VAN and GUA occured at +0.59 V and +0.48 V vs. Ag/AgCl at GNF/GCE, under optimum experimental condition. A well-defined peak potential window (~160 mV) for the oxidation of VAn and GUA were observed in the modified electrode. Calibration curves of VAN and GUA were attained in the ranges of 0.1 × 10–7 M to 53 × 10–6 M and 0.3 × 10–7 M to 46 × 10–6 M with correlation coefficient of 0.9966 and 0.9951, respectively. A greater sensitivity and the detection limit of VAN and GUA at 1.24 × 10–8 M and 0.98 × 10–8 M were obtained by using mediator and metal free modified electrode system in phosphate buffer medium. The present method is quite modest and robustic for the detection of VAN and GUA at a trace level. Graphical abstractSensitive electrochemical method for the quantitative detection of vanillin and guaiacol as food additive using defect-free graphene nanoflakes. Well-resolved oxidation peak current was shown in both analytes by differential pulse voltammetry method. The present method can be used for the simultaneous detection of vanillin and guaiacol in food samples

Enhanced amperometric detection of metronidazole in drug formulations and urine samples based on chitosan protected tetrasulfonated copper phthalocyanine thin-film modified glassy carbon electrode.

An enhanced electrocatalytic reduction of metronidazole antibiotic drug molecule using chitosan protected tetrasulfonated copper phthalocyanine (Chit/CuTsPc) thin-film modified glassy carbon electrode (GCE) has been developed. An irreversible reduction occurs at -0.47V (vs. Ag/AgCl) using Chit/CuTsPc modified GCE. A maximum peak current value is obtained at pH1 and the electrochemical reduction reaction is a diffusion controlled one. The detection limit is found to be 0.41nM from differential pulse voltammetry (DPV) method. This present investigation method is adopted for electrochemical detection of metronidazole in drug formulation and urine samples by using DPV method.

Mediator-free simultaneous determination of acetaminophen and caffeine using a glassy carbon electrode modified with a nanotubular clay

AbstractThe authors describe a voltammetric method for the simultaneous determination of acetaminophen (ACOP) and caffeine (CAF) using a glassy carbon electrode modified with a Nafion® protected halloysite nanotubular clay (GCE). Enhanced electrocatalytic oxidation behavior was observed at pH 4.5 in acetate buffer medium, with oxidation peak potentials of + 0.21 V for ACOP and + 1.0 V for CAF. The peak potential window (~ 800 mV) is quite large and hence differential pulse voltammetry (DPV) can be applied for simultaneous determination of both analytes. The calibration plots of ACOP and CAF are linear in the concentration ranges from 0.6 μM to 14 μM and 0.6 μM to 20 μM, and the detection limits are 1.1 × 10−8 M and 1.73 × 10−7 M, for ACOP and CAF, respectively. The method was applied to the determination of both analytes in drug formulations and human urine samples. Graphical abstractSchematic of a mediator-free voltammetric method for the simultaneous determination of acetaminophen and caffeine using glassy carbon electrode modified with a Nafion® protected halloysite nanotubular clay

Electrochemical deposition of a Zn-HNT/p(EDOT-co-EDOP) nanocomposite on LN SS for anti-bacterial and anti-corrosive applications

A copolymer composite of Zn-HNT/p(EDOT-co-EDOP) was deposited on low nickel stainless steel (LN SS) using an electrochemical polymerization method. The structure of the copolymer and the composite was confirmed by various analytical studies. In this work, the anticorrosion ability of the coatings was assessed in acidic solutions using an electrochemical method and their antibacterial activity was examined against marine bacteria.