Supercapacitors are beneficial as energy storage devices and can obtain high capacitance values greater than conventional capacitors and high power densities compared to batteries. However, in order to improve upon the overall cost, energy density, and charge-discharge rates, the electrode material of supercapacitors needs to be fine-tuned with an inexpensive, high conducting source. We prepared a Co(III) complex and polypyrrole (PPy) composite thin films (CoN 4 - PPy) that was electrochemically deposited on the surface of a glassy carbon working electrode. Cyclic voltammetry studies indicate the superior performance of CoN 4 -PPy in charge storage in acidic electrolyte compared to alkaline and organic solutions. The CoN 4 -PPy material generated the highest amount of specific capacitance (up to 721.9 F/g) followed by Co salt and PPy (Co-PPy) material and PPy alone. Cyclic performance studies showed the excellent electrochemical stability of the CoN 4 -PPy film in the acidic medium. Simply electrochemically depositing an inexpensive Co(III) complex with a high electrically conducting polymer of PPy delivered a superior electrode material for supercapacitor applications. Therefore, the results indicate that novel thin films derived from Co(III) metal complex and PPy can store a large amount of energy and maintain high stability over many cycles, revealing its excellent potential in supercapacitor devices.

A nanocomposite of a dichloro-amido-macrocyclic cobalt-(III) complex (1) and graphene was developed and characterized using various microscopic and spectroscopic techniques such as X-ray photoelectron spectroscopy, transmission electron microscopy, scanning electron microscopy and Raman spectroscopy. The nanocomposite was evaluated for electrocatalytic activity toward oxygen reduction reaction (ORR) in fuel cell applications. This complex (1) showed efficiency in a wide range of pH (acidic and basic) conditions for successful ORR. Apart from pH studies, the ratio of electrocatalyst 1 to graphene was varied for developing the optimal ORR catalyst. The use of graphene as a carbon support along with 1 in ORR studies not only resulted in increased current density but also a positive shift of the reduction potential by 140 mV (with respect to the Ag/AgCl reference electrode). Investigation of the catalytic mechanism using rotating disk electrode and rotating ring-disk electrode studies revealed its mechanism in acidic and basic conditions. The ORR was found to be a four-electron process in both pH conditions. The rate constant of ORR activity was found to be 3.85 × 10 5 mol −1 s −1 at pH 2.0. The efficiency of the nanocomposite in ORR indicates the advantage of using both 1 and graphene for fuel cell applications.

Platinum electrodes are commonly used electrocatalysts for oxygen reduction reactions (ORR) in fuel cells. However, this material is not economical due to its high cost and scarcity. We prepared an Mn(III) catalyst supported on graphene and further coated with polydopamine, resulting in superior ORR activity compared to the uncoated PDA structures. During ORR, a peak potential at 0.433 V was recorded, which is a significant shift compared to the uncoated material’s −0.303 V (both versus SHE). All the materials reduced oxygen in a wide pH range via a four-electron pathway. Rotating disk electrode and rotating ring disk electrode studies of the polydopamine-coated material revealed ORR occurring via 4.14 and 4.00 electrons, respectively. A rate constant of 6.33 × 106 mol−1s−1 was observed for the polydopamine-coated material–over 4.5 times greater than the uncoated nanocomposite and superior to those reported for similar carbon-supported metal catalysts. Simply integrating an inexpensive bioinspired polymer coating onto the Mn-graphene nanocomposite increased ORR performance significantly, with a peak potential shift of over +730 mV. This indicates that the material can reduce oxygen at a higher rate but with lower energy usage, revealing its excellent potential as an ORR electrocatalyst in fuel cells.

A major benefit to nanomaterial based-medicine is the ability to provide nanosized vehicles for sporadic metabolites. Here, we describe how the conjugation of valuable ginseng secondary metabolites (ginsenoside Rb1 or Rg1) with carbon nanotubes (CNT) can enhance their anti-proliferative and anti-cancer effects. Ginsenoside-CNT conjugate (Rb-CNT or Rg-CNT) permitted the ginsenosides to be used at a low dose, yet achieve a higher incidence of cancer killing. We were able to demonstrate that the ginsenoside-CNT conjugate can decrease cell viability up to 62% in breast cancer cells (MCF-7) and enhance antiproliferation of drug-resistant pancreatic cancer cells (PANC-1) by 61%. The interaction of the ginsenoside-CNT conjugate with breast cancer cells was studied using Raman Spectroscopy mapping. Total transcriptome profiling (Affymetrix platform) of MCF-7 cells treated with the ginsenoside-CNT conjugate shows that a number of cellular, apoptotic and response to stimulus processes were affected. Therefore, our data confirmed the potential use of CNT as a drug delivery system.

In this study, an injectable thermoresponsive hydroxypropyl guar-graft-poly(N-vinylcaprolactam) (HPG-g-PNVCL) copolymer was synthesized by graft polymerization. The reaction parameters such as temperature, time, monomer, and initiator concentrations were varied. In addition, the HPG-g-PNVCL copolymer was modified with nano-hydroxyapatite (n-HA) by in situ covalent cross-linking using divinyl sulfone (DVS) cross-linker to obtain HPG-g-PNVCL/n-HA/DVS composite material. Grafted copolymer and composite materials were characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, proton nuclear magnetic resonance spectroscopy (1H NMR), and differential scanning calorimetry. The morphology of the grafted copolymer (HPG-g-PNVCL) and the composite (HPG-g-PNVCL/n-HA/DVS) was examined using scanning electron microscopy (SEM), which showed interconnected porous honeycomb-like structures. Using Ultraviolet−visible spectroscopy, low critical solution temperature for HPG-g-PNVCL was observed at 34 °C, which is close to the rheology gel point at 33.5 °C. The thermoreversibility of HPG-g-PNVCL was proved by rheological analysis. The HPG-g-PNVCL hydrogel was employed for slow release of the drug molecule. Ciprofloxacin, a commonly known antibiotic, was used for sustainable release from the HPG-g-PNVCL hydrogel as a function of time at 37 °C because of viscous nature and thermogelation of the copolymer. In vitro cytotoxicity study reveals that the HPG-g-PNVCL thermogelling polymer works as a biocompatible scaffold for osteoblastic cell growth. Additionally, in vitro biomineralization study of HPG-g-PNVCL/n-HA/DVS was conducted using a simulated body fluid, and apatite-like structure formation was observed by SEM.