Enhanced antibacterial activity of a novel biocompatible triarylmethane based ionic liquid-graphene oxide nanocomposite.

Biofilm formation on medical implants and devices has been a severe concern that results in their impaired performance and life-threatening complications. Thus, development of novel functional coatings for infection prone surfaces with biofilm inhibiting characteristics is of prime significance considering the rapid emergence of multidrug resistant bacteria. Herein we present a novel nanocomposite derived from Graphene Oxide (GO) and a newly developed functional Ionic liquid (IL) obtained through a metathesis reaction between a triarylmethane dye hexamethyl pararosaniline chloride or crystal violet (CV) and sodium dodeceyl sulfate (SDS) to yield [CV][DS] (hexamethyl pararosaniline dodecyl sulfate). This highly biocompatible [CV][DS]-GO nanocomposite exhibit more than four times improved antibacterial activity in comparison to bare GO against both gram negative Escherichia coli (E. coli) and gram positive Staphylococcus aureus (S. aureus). As suggested by XRD, FTIR and UV absorption and SEM results improved activity of [CV][DS]-GO nanocomposite is ascribed to the synergistic effect of reduced nanocomposite sheet thickness, enhanced amphiphilicity imparted by dodecylsulfate (DS), exposed active ArN+ groups of CV and some inherent functionalities of GO. This is also complemented by the ruptured and diffused S. aureus cell walls as observed in bacterial SEM result. In contrast, the nanocomposites of the precursors with GO do not demonstrate any significant antibacterial effect. Coatings developed using GO upon infestation with E. coli revealed significant biofilm formation after 48 and 72 h of incubation while [CV][DS]-GO coated surface demonstrated no colony growth under similar circumstances. Thus, [CV][DS]-GO nanocomposite coatings exhibit excellent resistance to bacterial growth even up to 72 h incubation signifying its bactericidal effect. Therefore, the developed nanocomposite may be considered as one of the improved antibacterial wash resistant coating material for biomedical devices and surfaces susceptible to to biofilm formation.

Remarkably high Pb2+ binding capacity of a novel, regenerable bioremediator Papiliotrema laurentii RY1: Functional in both alkaline and neutral environments.

The ability of P. laurentii strain RY1 to remediate lead (Pb2+) from water was investigated in batch and column studies. The lead removal ability of non-viable biomass, non-viable biomass immobilised on agar-agar (biobeads) and agar-agar at different pH was compared in batch studies. It was found that among the three, biobeads have maximum ability to remove Pb2+ followed by biomass and agar-agar beads. Maximum and almost equal lead removal by biobeads was observed at both neutral and alkaline pH making it a novel and more applicable bioremediator as all other reported bioremediators have a single pH for optimum activity. Studies were performed to determine the optimum conditions for lead removal from aqueous solutions for biobeads. The physical and chemical characterization of the biobeads before and after Pb2+ biosorption was done by using S.E.M. and F.T.I.R. respectively. The adsorption of Pb2+ on biobeads obeyed the Langmuir adsorption isotherm and pseudo first order kinetics. These mean that the Pb2+ binding sites are identical, located on the surface of the adsorbant and the rate of Pb2+ removal from aqueous solution is directly proportional to the number of Pb2+ binding sites on the biobeads. The thermodynamics of the biosorption process is also investigated. The binding capacity of the biobeads in batch study was found to be 52.91mg/gm which is higher in comparison to other reported yeast bioremediators. The used biobeads can be desorbed using 0.1(M) CaCl2. The desorbed biobeads can be used subsequently for several cycles of lead removal making it cost-effective. Column studies were also performed for biobeads with the help of Thomas model for examining its suitability for industrial application. Maximum specific lead uptake of the biobeads when applied in the column was found to be 58.26mg/gm which being promising makes it suitable for application in industries involved in the treatment of wastewater contaminated with high amounts of lead. The high mass transfer co-efficient indicate that small sized column can be used effectively to remove high amounts of lead which makes the bioremediation process by the biobeads more economical and advantageous for industrial application. Several factors like effectiveness of the biobeads in Pb2+removal at both neutral and alkaline pH, reusability, high mass transfer co-efficient, regenerability and high binding capacity makes it a novel versatile, cost-effective and high utility bioremediator.

Fabrication of morphologically modified strong supramolecular nanocomposite antibacterial hydrogels based on sodium deoxycholate with inverted optical activity and sustained release.

Low Molecular Weight (LMWG) gelators are small molecules that form supramolecular self-assembly involving physical forces and are highly biocompatible. However, fragility of these physical gels restricts their applicability where gels of higher mechanical strength are required. Herein, we have developed two different types of 2-D carbon nanomaterials viz. graphene oxide (GO) and carbon nanosheet (CNS) embedded sodium deoxycholate (NaDC) hydrogels. XRD, scanning electron microscopy (SEM), rheology and CD studies suggest significant modification of morphological, mechanical, viscoelastic and optical properties of the nanocomposite gels which is ascribed to the presence of the 2D nanotemplates and participation of different surface functionalities of GO and CNS in the gelation process. The overall shear resistance of both the nanocomposite hydrogels upto a shear rate of 300 shears/s-1 and above reveals tremendously improved mechanical stability with respect to the pure gels. The increased shear strength of the GO/NaDC and CNS/NaDC hydrogels is attributed to their 3-4 times broader and longer ribbon like structures in comparison to the fibrous structure of pure gels. The intact ribbon like morphology and greater entanglement impart 10 folds greater viscosity to GO-NaDC hydrogels as compared to better elasticity of CNS-NaDC hydrogels possessing broken ribbon edges. Most interestingly both GO and CNS influence the optical activity of the gels and presence of GO results in inversion of optical activity. The GO-NaDC gels are also found to demonstrate antibacterial activity against E. coli, and S. aureus. Thus, these extraordinarily modified mechanically strong gels have enhanced potential for use in tissue engineering, enantioselective and sustained drug delivery, topical antibiotics and other biomedical applications.

Investigation of the Origin of Voltage Generation in Potentized Homeopathic Medicine through Raman Spectroscopy.

BACKGROUND: For the study of homeopathic medicines in proper perspective, emerging techniques in material science are being used. Vibrational spectroscopy is one such tool for providing information on different states of hydrogen bonding as an effect of potentization. The associated change in electrical properties is also correlated with this effect. OBJECTIVE: From the vibrational spectra, the changes in hydrogen bonding due to dilution followed by unidirectional vigorous shaking (together termed potentization) of 91% ethanol and two homeopathic medicines Chininum purum and Acidum benzoicum have been studied. The aim was to correlate the result with the change in the electrical properties of the system. METHODS: Raman spectroscopy was used to study the vibrational spectra. A U-shaped glass tube (electrochemical cell), where one arm contained bi-distilled water and the other arm alcohol/homeopathic medicine (the arms being separated by a platinum foil), was used to measure the voltage generated across two symmetrically placed platinum electrodes. RESULTS: For all samples, it was observed that potentization affected the intensity of OH stretching bands at the frequencies 3240 cm-1, 3420 cm-1 and 3620 cm-1, corresponding to strong hydrogen bond, weak hydrogen bond and broken hydrogen bond, respectively. With the increase in potency, in the presence and absence of the two medicines in ethanol, the number of OH groups linked by strong hydrogen bonds decreased, while the number of OH groups with weak hydrogen bonds increased. With the increase in potentization, the number of OH groups with broken hydrogen bonds showed a difference in the presence and absence of the medicine.The voltage measurements for ethanol show that, with succussion, the magnitude of voltage increased with the two medicines at lower potencies, but not at higher potency where the voltage is lower. Acidum benzoicum, which is acidic in nature, had higher voltage values (113mV, 130 mV and 118 mV at 6C, 30C and 200C, respectively), compared with Chininum purum, which is basic in nature (20 mV, 85 mV and 65 mV at 6C, 30C and 200C, respectively). CONCLUSION: The experimental results indicate a correlation between the vibrational and electrical properties of the homeopathic medicines Acidum benzoicum and Chininum purum at different potencies.

Effect of Homeopathic Dilutions of Cuprum Arsenicosum on the Electrical Properties of Poly(Vinylidene Fluoride-Co-Hexafluoropropylene).

BACKGROUND: We report the effects of nanoparticles in homeopathic preparations of copper salts on the electrical properties of polymer film. Previous work showed that the incorporation of metal-derived homeopathic medicines increases the dielectric constant and alternating current (AC) conductivity of an electroactive polymer film that is commonly used as a capacitor in the electronic industry.We report here the effect of dilution of one homeopathic medicine, Cuprum arsenicosum (CuAs), at 200C potency on the electrical properties of the polymer film of poly(vinylidene fluoride-co-hexafluoropropylene). METHODS: CuAs 200c was incorporated in the film by the solution casting method. The electrical characteristics were measured at different frequencies using an inductance, capacitance, and resistance meter. Fourier transform infrared spectroscopy (FTIR) was performed to detect phase change in the polymer film due to the incorporation of CuAs. Morphology and particle size were studied using field emission scanning electron microscopy (FESEM) and energy dispersive X-ray (EDX) spectroscopy. RESULTS: At 10 kHz frequency, both dielectric constant and AC conductivity increased approximately 18 times for the polymer film when incorporated with 2 mL CuAs at 200C potency. FTIR indicated the increase in conducting phase, while FESEM and EDX confirmed the presence of spherical CuAs particles. CONCLUSION: The incorporation of CuAs in the electroactive polymer film enhances the conductivity and dielectric constant. We conclude that these changes arise from the change in phase of the polymer film, and because of the presence of two different metals that affects the interfacial polarization.

Dual release kinetics in a single dosage from core-shell hydrogel scaffolds.

The development of drug delivery systems with microencapsulated therapeutic agents is a promising approach to the sustained and controlled delivery of various drug molecules. The incorporation of dual release kinetics to such delivery devices further adds to their applicability. Herein, novel core-shell scaffolds composed of sodium deoxycholate and trishydroxymethylaminomethane (NaDC-Tris) have been developed with the aim of delivering two different drugs with variable release rates using the same delivery vehicle. Data obtained from XRD studies, sol-gel transition temperature measurement, rheology and fluorescence studies of the core-shell systems indicate a significant alteration in the core and the shell microstructural properties in a given system as compared to the pure hydrogels of identical compositions. The release of the model drugs Fluorescein (FL) and Rhodamine B (RhB) from the shell and the core, respectively, of the two core-shell designs studied exhibited distinctly different release kinetics. In the 25@250 core-shell system, 100% release of FL from the shell and 19% release of RhB from the core was observed within the first 5 hours, while 24.5 hours was required for the complete release of RhB from the core. For the 100@250 system, similar behaviour was observed with varied release rates and a sigmoidal increase in the core release rate upon disappearance from the shell. Cell viability studies suggested the minimal toxicity of the developed delivery vehicles towards NMuMG and WI-38 cells in the concentration range investigated. The reported core-shell systems composed of a single low molecular weight gelator with dual release kinetics may be designed as per the desired application for the consecutive release of therapeutic agents as required, as well as combination therapy commonly used to treat diseases such as diabetes and cancer.