Bismuthene nanosheets produced by ionic liquid assisted grinding exfoliation and their use for oxygen reduction reaction

We report the simple synthesis of bismuthene nanosheets (BiNS) by ionic liquid assisted grinding exfoliation, followed by size selection sequential centrifugation steps for the first time. The exfoliation process results in the formation of self-assembled spherule-like superstructures with abundant edge sites, which are able to catalyze the oxygen reduction reaction (ORR) via a two-electron pathway, with a higher efficiency than the bulk Bismuth. We rationalize the enhanced ORR activity of the BiNS to: (i) the presence of 1 dimensional topological edge states, which provide strong conduction channels for electron hopping between the bismuth layers and (ii) the more active role of edge sites in facilitating O(2) adsorption and dissociation of O–O bonds compared to the basal plane. The present study provides a pathway for employing 2D topological insulators as a new class of electrocatalysts for clean energy applications

Live Cell Integrated Surface Plasmon Resonance BiosensingApproach to Mimic the Regulation of Angiogenic Switch upon Anti-CancerDrug Exposure

In this work, we report a novel surface plasmon resonance (SPR) based live-cell biosensing platform to measure and compare the binding affinity of vascular endothelial growth factor (VEGF) to vascular endothelial growth factor receptor (VEGFR) and VEGF to bevacizumab. Results have shown that bevacizumab binds VEGF with a higher association rate and affinity compared to VEGFR. Further, this platform has been employed to mimic the in vivo condition of the VEGF?VEGFR angiogenic switch. Competitive binding to VEGF between VEGFR and bevacizumab was monitored in real-time using this platform. Results demonstrated a significant blockage of VEGF?VEGFR binding by bevacizumab. From the results, it is evident that the proposed strategy is simple and highly sensitive for the direct and real-time measurements of bevacizumab drug efficacy to the VEGF?VEGFR angiogenic switch in living SKOV-3 cells

Definitive evidence for fast electron transfer at pristine basal plane graphite from high-resolution electrochemical imaging

After all, it's active: High-resolution scanning electrochemical cell microscopy (SECCM) demonstrates that electron transfer at the basal plane of highly oriented pyrolytic graphite (HOPG) is fast. This finding requires radical revision of the current textbook model for HOPG electrochemistry

Editorial

The Indian National Young Academy of Sciences often called “INYAS” functioning under the tutelage of the Indian National Science Academy (INSA), New Delhi is a vibrant and talented academy of young scientists. INYAS was established in December 2014 and is the first and only such young academy in India. At present, INYAS has over 100 members out of which 30% members are females. The Vision of INYAS is to attract the youth towards science, disseminate the excitement of science at pre-college, college and university levels, and establish a network of young scientists in India. Considering the importance of science communication, dissemination and outreach, INYAS do serve as a crusader and embraces different stakeholders such as faculties, researchers from academia, research institutes, polytechnic, schools, industries, incubation centers, policy-makers and decision-makers

Development of a disposable electrode modified with carbonized, graphene‐loaded nanofiber for the detection of dopamine in human serum

A one‐step electrode surface modification is proposed in which a disposable, screen‐printed carbon electrode is functionalized with carbonized, electrospun polyacrylonitrile (PAN)‐loaded graphene (G) nanoparticles to form a composite, CPAN5G‐4x. The electrochemical behavior of the CPAN5G‐4x electrode was examined by cyclic voltammetry and electrochemical impedance spectroscopy. Scanning electron microscopy and X‐ray diffraction were used to characterize the surface morphology and physical properties of the carbonized composite nanofibers before and after modification. The modified electrode was found to be effective for the detection of dopamine (DA) using square‐wave voltammetry (SWV) in the presence of interfering substances such as ascorbic acid and uric acid. With the addition of sodium dodecyl sulfate (SDS) to an optimized solution of phosphate‐buffered saline (PBS) at a pH of 2, the fabricated electrode exhibited enhanced electrocatalytic activity toward the oxidation of DA relative to PBS without SDS at a pH of 7.4. The SWV current displayed a linear response to DA concentrations ranging from 0.5 to 100 μ M , with a limit of detection of 70 n M ( S / N  = 3) and a sensitivity of 1.4258 μA μ M −1 cm −2 . Finally, the CPAN5G‐4x electrode was used to determine DA levels in human serum. The modified electrode can potentially be harnessed for further electrochemical biosensor applications. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131 , 40858.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108015/1/app40858.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/108015/2/app40858-sup-0001-suppinfo.pd

Electrospun Carbon Nanofiber Webs with Controlled Density of States for Sensor Applications

Electrospun carbon nanofiber (CNF) webs with controlled density of states (DOS) are synthesized through varying the carbonization conditions to manipulate the concentration of nanosized graphite domains. These materials exhibit adjustable electrochemical activity and biosensitivity: both electron transfer kinetics for various redox systems and direct electron transfer efficiencies with enzymes increase with the DOS of the CNF webs.United States. Dept. of Energ

A new view of electrochemistry at highly oriented pyrolytic graphite

Major new insights on electrochemical processes at graphite electrodes are reported, following extensive investigations of two of the most studied redox couples, Fe(CN)64–/3– and Ru(NH3)63+/2+. Experiments have been carried out on five different grades of highly oriented pyrolytic graphite (HOPG) that vary in step-edge height and surface coverage. Significantly, the same electrochemical characteristic is observed on all surfaces, independent of surface quality: initial cyclic voltammetry (CV) is close to reversible on freshly cleaved surfaces (>400 measurements for Fe(CN)64–/3– and >100 for Ru(NH3)63+/2+), in marked contrast to previous studies that have found very slow electron transfer (ET) kinetics, with an interpretation that ET only occurs at step edges. Significantly, high spatial resolution electrochemical imaging with scanning electrochemical cell microscopy, on the highest quality mechanically cleaved HOPG, demonstrates definitively that the pristine basal surface supports fast ET, and that ET is not confined to step edges. However, the history of the HOPG surface strongly influences the electrochemical behavior. Thus, Fe(CN)64–/3– shows markedly diminished ET kinetics with either extended exposure of the HOPG surface to the ambient environment or repeated CV measurements. In situ atomic force microscopy (AFM) reveals that the deterioration in apparent ET kinetics is coupled with the deposition of material on the HOPG electrode, while conducting-AFM highlights that, after cleaving, the local surface conductivity of HOPG deteriorates significantly with time. These observations and new insights are not only important for graphite, but have significant implications for electrochemistry at related carbon materials such as graphene and carbon nanotubes

Hybrid materials of pyrene substituted phthalocyanines with single-walled carbon nanotubes: structure and sensing properties

Hybrid materials of single walled carbon nanotubes (SWCNT) were obtained by their non-covalent functionalization with asymmetrically polyoxyethylene substituted phthalocyanines (MPc-py (M = Cu, Co, 2H)) bearing one pyrene group as a substituent. The attachment of MPc-py molecules onto the SWCNT surface have been confirmed using Raman spectroscopy, SEM, TEM and thermogravimetric analysis. The pyrene substituents were introduced to the phthalocyanine macrocycle in order to improve π–π interaction between the MPc-py and SWCNT. The effect of the central metal on the formation and sensor properties of the MPc-py within the hybrids has been verified. It has been shown that the electrical response of the hybrid films to ammonia vapor in the concentration range of 10–50 ppm changes in the following order CuPc-py > CoPc-py > H2Pc-py, which was found to be in good correlation with the amount of phthalocyanine molecules adsorbed onto the SWCNT walls, as estimated by thermogravimetric analysis (TGA)