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Nanoscience and Nanotechnology in Biology and Medicine |
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Open Access

Nanoscience and Nanotechnology in Biology and Medicine

Short Communication

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Advanced Materials 2019: Scanning tunneling microscopy and spectroscopy of wet chemically synthesized porous graphene nanoribbons- Kaitlyn Parsons, University of Illinois at Urbana-Champaign

Kaitlyn Parsons*, Adrian Radocea, Mohammad Mehdi Pour, Tao Sun1, Narayana Aluru, Alexander Sinitskii and Joseph W Lyding

The bottom-up wet chemical synthesis of Graphene Nanoribbons (GNRs) opens interesting opportunities for tailoring the GNR structure with atomic precision. Atomically precise porous GNRs are a replacement chemically synthesized variation that the fabrication procedures yielding multiple pores during a single ribbon and therefore the electronic details of the ribbon haven't been reported. during this study, porous GNRs are dry contact transferred in ultrahigh vacuum to wash silicon and III-V semiconducting substrates and examined using UHV Scanning Tunneling Microscopy (STM) and Spectroscopy (STS). STM imaging confirms the expected porous structure and indicates a singular electronic feature at the graphene nanopores and STS measurements indicate a 2.0 eV band gap. These results are compared to first-principles DFT simulations during which an increased local density of states at the pores is predicted. A GW correction predicts a 2.89 eV band gap. Illumination of pore effects in GNRs contributes to an increased understanding of the tunability of GNR electronic structure. Porous GNRs have potential applications in molecular filtration, detection and DNA sequencing.

Moore’s law is that the observation that the transistor density during a chip will double approximately every two years. Scaling below the 10nm node limit for silicon transistors introduces excessive heating and quantum effects, like tunneling of electrons that degrade the performance of the logic device. New materials are required so as to continue scaling and increasing microprocessor chip performance. Two-dimensional materials possess an inherent advantage for continued scaling and have promising electrical properties. Two-dimensional atomic crystals were first experimentally isolated from bulk material in 2004 by K. S. Novoselov, A. K. Geim, et al. during this work, mechanical exfoliation using tape was wont to pull apart layers of highly oriented pyrolytic graphite. This highly reliable procedure leads to a two-dimensional monolayer of carbon atoms during a hexagonal lattice, a cloth referred to as graphene. before this work, free-standing two-dimensional films were thought to be thermodynamically unstable below a critical thickness consisting of a couple of atomic layers. Typically, thin films segregate or decompose thanks to the decreasing film thickness and decreasing melting temperatures. Despite this fact, Novoselov et al. prepared a spread of two-dimensional films using micromechanical cleavage under ambient conditions following the success of graphene. Van der Waals forces hold the layers together within the three-dimensional form. Repeated micromechanical cleavage breaks these weak bonds to make two-dimensional films.

Short Communication

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Advanced Materials 2019: Structural investigation of Si nanoparticles-carbon nanofiber composite as flexible anode for highrate lithium-ion batteries- Vahide Ghanooni Ahmadabadi, Deakin University

Vahide Ghanooni Ahmadabadi*, Kamyar Shirvanimoghaddam, Nibin Showkath, Robert Kerr, Minoo Naebe and Ying Chen

Self-standing, binder-free and versatile anodes of silicon-carbon nanofiber composite are fabricated via electrospinning. the speed capability of the anodes of various fibers diameter are investigated for lithium-ion batteries. The embedded silicon nanoparticles inside carbon fibers are effectively shielded from direct exposure to the electrolyte. This structure results in vastly improved capacity retention during galvanostatic half-cell cycling. Cycling results showed that an electrode with 230 nm fiber diameter has enhanced cyclability and rate capability in comparison to at least one with 620 nm diameter. Post-cycling investigations of the electrodes via SEM (Scanning Electron Microscopy) and EIS (Electrochemical Impedance Spectroscopy) reveals a far better structural stability and fewer electrical impedance build-up with cycling for the electrode with thinner CNFs. This behavior may be a results of a lower linear density of the SiNPs along the skinny CNFs which avoids the formation of SiNPs clusters within the CNFs. Accumulated stress-strain over lithiation/de-lithiation is made within the thicker CNFs thanks to the quantity change of Si which results in breakage of the CNFs.

 

Lithium-ion batteries are a transportable power source with a high energy density and stable electrochemistry that have changed our daily lives. because of technological developments in areas like smartphones and electric vehicles, there's an increased demand for top energy density and fast-charging lithium-ion batteries which will provide greater power capacity. Recent battery fires and explosions have also led to a desire to enhance the security of energy storage systems. the planning of a completely unique negative electrode material can address the energy density, safety, and rate performance problems with conventional graphite electrodes that cause unsatisfactory electrochemical performances like low theoretical capacity (372 mAh/g), irreversible electrolyte and lithium consumption supported solid electrolyte interphase (SEI) formation, slow lithium intercalation, and dendrite formation during fast charging. Resolving these issues has been the main target of publications on novel lithium-ion battery anodes.

Electrospinning has been identified because the most promising route for designing novel anode materials and structures, due to the straightforward process setup and big variety of electrospinnable materials. The electrospinning process can encourage the implementation of existing anode material research supported the method having the ability to mass-produce anodes. Although nanofiber anode material research has mainly focused on developing carbon-, silicon-, and tin-based materials to exchange graphite anodes, there are numerous publications on a good sort of anode materials because of the merits of the electrospinning process. Here, examples to style the advanced anode materials supported the electrospun nanofibers are presented. Heteroatoms and pores were employed to extend the precise capacity of carbon anode. Carbon composited and nanostructured metal and metal oxide anode materials were designed to enhance cycling and rate performance. Lithiophilic nanofiber was fabricated to reinforce the reversibility of lithium plating and stripping. it's necessary to review previous research into electrospun nanofiber-based anode materials to determine better strategies for implementing nanofiber anode materials in commercial lithium-ion batteries and designing novel nanofiber anode materials for next-generation batteries.

Short Communication

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Advanced Materials 2019: The unit cell prediction of two-dimensional supramolecule by STUN-BH-DMD method and molecular dynamics simulation- Tsu-Hsun Hou- National Sun Yat-sen University

Tsu-Hsun Hou*, Chia-Hao Su1, Shih-Jye Sun, Shin-Pon Ju1, and Che-Hsin Lin

The unit of two-dimensional STA supramolecule on a virtual graphene surface was predicted during this study. The DRIEDING field was wont to describe the interatomic interactions and therefore the Electrostatic Surface Potential (ESP) charges obtained by the semi-empirical initially package VAMP with the NDDO (Neglect of Diatomic Differential Overlap) Hamiltonians approximation method of PM6 (Parameterization Method 6) was used for the DREIDING potential. First, the Stochastic Tunneling-Basin-Hopping-Discrete molecular dynamics method (STUN-BH-DMD) was wont to predict the foremost stable STA layer on the virtual graphene surface. The box shape was adjusted during the STUN-BH-DMD search process and therefore the ordered unit of STA supramolecule was predicted. The molecular dynamics simulations were wont to investigate the thermal stability and diffusion behaviors of STA supramolecule. The energy-temperature profiles were wont to pinpoint the temperatures, at which the STA supramolecule structure begins damaged and therefore the mean-square displacement profiles were wont to investigate the dynamical behaviors of STA supramolecules at different temperatures also as deriving the diffusion coefficients of STA.

The molecular structure and dynamics at the interface between a sheet surface and a posh fluid is of considerable interest, e.g., within the context of lubrication, adhesion, molecular recognition phenomena at interfaces, or for the organization of molecules possibly undergoing topochemi- cal reactions. Recent scanning tunneling microscopy (STM) studies at the interface between organic solutions or melts of long chain alkanes and straightforward alkyl derivatives and therefore the basal plane of graphite reveal highly ordered lamellar structures. The STM images confirm an earlier model proposed on the idea of adsorption isotherm and enthalpy measurements. It sug- gests that over a substantial range of concentrations the solute molecules physisorb in all-trans conformation parallel to the surface, forming densely packed monolayers. A de- tailed analysis of the STM results allows, additionally, to de- termine the commensurability between substrate and adsor- bate lattices, both along the molecular axes of the adsorbate also as along the lamellae.’ The time resolution of the STM experiment, however, is restricted to the millisecond duration. While this is often sufficient to watch the cooperative reor- ganization of a couple of molecules within the monolayers, it is way too slow to observe the intramolecular dynamics in this case. Here we combine STM results with computer simula- tions to get further insight. Computer simulations are now among the quality theoretical approaches to adsorption phenomena on solid surfaces. Methods like Monte Carlo or molecular dynamics (MD) are useful tools in the study of the translational and orientational ordering of adsorbates, their commensurabi- lity or incommensurability with the substrate, the dynamics of adsorbates, and therefore the universal and nonuniversal aspects of surface phase transitions.

Short Communication

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Emerging Materials Congress 2019: Preclinical safety of topically administered nanostructure lipid carriers (NLC) indicated for wound healing: biodistribution and toxicity studies- C. Vairo, BioPraxis Research AIE

C. Vairo* and G. Gainza

Re-activation of the recuperation system is a primary mission withinside the area of persistent wound recuperation. Lipid-nanoparticles, specifically nanostructured lipid carriers (NLC), own extraordinarily beneficial characteristics (biodegradability, biocompatibility and long-time period balance) and are appropriate for drug transport. Moreover, they keep wound moisture because of their occlusive residences, that have been related to multiplied recuperation rates. In the mild of above, NLC had been significantly used for wound recuperation but, to date, there may be no protection-preclinical research of topically administered lipid-nanoparticles; thus, here, biodistribution research had been carried out in rats with the NLC formerly advanced via way of means of our studies organization, the usage of technetium-99m (99mTc-NLC) as radiomarker. 99mTc-NLC remained at the wound for twenty-four h and no systemic absorption become discovered after management. Moreover, toxicological research had been carried out to evaluate NLC protection after topical management. NLC had been non-cytotoxic, non-touchy and non-irritant/corrosive. Overall, it is probably concluded that advanced NLC remained on the management location, probably exerting a neighborhood effect, and had been secure after topical management on wounds. In current years, lipid-nanoparticles, i.e. stable lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC), have attracted a whole lot interest as powerful, biodegradable, biocompatible and non-poisonous carriers, showing many good enough functions for dermal software of cosmetics and pharmaceutics. Consequently, SLN and NLC had been extensively taken into consideration as appropriate and green structures for enhancing wound recuperation due to their occlusive residences that boom pores and skin hydration and beautify drug penetration. Therefore, using those lipid nanoparticles is an exciting approach for persistent wound remedy as they sell the right wound mattress that might re-spark off the recuperation system. Wound recuperation is an essential and complicated physiological system required to regenerate and restore any broken location withinside the shortest time. This system begins offevolved with an inflammatory phase, accompanied via way of means of proliferative and transforming ones. Chronic wounds generally tend to stall withinside the inflammatory phase, hampering development into the proliferative step and delaying or preventing the wound recuperation system; thus, affecting the patient's best of life. In view of the foregoing, the improvement of powerful and secure healing options capable of re-spark off recuperation is a primary breakthrough. To date, NLC have proven extra balance and loading capability in comparison to SLN because of their composition, as NLC are composed of a mix of stable and liquid lipids that results in a much less ordered internal shape in comparison to the crystalline matrix of SLN. Moreover, numerous studies corporations have tested the efficacy of NLC as drug transport structures to enhance wound recuperation. Previous research posted via way of means of our studies organization have proven that epidermal increase factor (EGF) loaded NLC more advantageous wound recuperation each in vitro and in vivo and LL37 (a human antimicrobial peptide) loaded NLC progressed wound closure.

Short Communication

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Emerging Materials Congress 2019: Dielectric relaxation and ac conductivity of nano sized polyaniline-cobalt oxide composites- Narsimha Parvatikar- APS College of Engineering

Narsimha Parvatikar*, M V N Ambika Prasad, B M Satish and S C Sharma

The nano sized PANI/CO3O4 composites were synthesized using in place deposition technique by placing fine graded CO3O4 in polymerization mixture of aniline. this is often the only step polymerization process for the direct synthesis of emeraldine salt phase of polymer. Low frequency dielectric studies were administered on pressed pellets of PANI/ CO3O4 with various concentrations of cobalt oxide (10, 20, 30, 40, and 50 wt% of CO3O4 in PANI). The ac conductivity and dielectric properties are studied within the frequency range from 102 to 106 Hz. The results are interpreted in terms of polarons and bipolarons, which are liable for the dielectric relaxation mechanism and frequency dependence of conductivity. it's found that a.c.measurements at temperature could function a parallel thanks to the time consuming d.c. conductivity versus temperature technique, to detect the thermal degradation of the transport properties in conducting polymers. it's observed that the charge motion via creation/annihilation of polarons and bipolarons increases because the weight percentage of the composite is increased. The results obtained for these composites are of scientific and technological interest.

The discovery of intrinsically conducting polymers like polyacetylene, polyaniline, polypyrrole, polythiophene, polyindole, etc. have emerged as a active materials cause a good range of applications. The useful properties of those polymers are tunable by adding inorganic nanoparticles to them. for instance , increase of conductivity, dielectric constant and dielectric loss with increase of V2O5 was recorded in polyaniline-V2O5 composites. an honest thermal stability and noticeable crystallinity were observed in polyaniline-silver nanocomposites. Increased conductivity with metal nanoparticles has been measured for polythiophene-nickel and polypyrrole-copper nanocomposites. Increase of magnetization and reduce of conductivity were noted for polyaniline-Iron nanocomposites. The optical band gap decreased and electrical conductivity increased in polyaniline when doped with Ag nps. These fundamental properties and their variations in several environments for polymer composites cause the applications of the sort gas sensors, supercapacitors, microwave and electromagnetic radiation absorbers, resistive switching devices etc. On our extensive literature survey, it's learned that polythiophene cobalt nanocomposites haven't been explored for dielectric and ac conductivity. within the present paper the results on morphology, dielectric properties and ac conductivity of polythiophene-cobalt (PTh-Co) nanocomposites are presented.

The nanocomposites with an organized structure usually provide a replacement functional hybrid, with synergistic properties over their single-component counterparts, which have attracted considerable attention for his or her potential applications. Polymer nanocomposites are an important class of polymers, which have wide applications during a number of di�erent industrial sectors and thus organic/inorganic nanocomposite materials have been extensively studied within the previous couple of decades. Conducting polymer nanocomposites possess the advantages of both low dimensional systems (nanostructure filler) and organic conductors (conducting polymer).

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Citations: 3677

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