فصلنامه نانو مقیاس
سال دوم شماره 3 (پیاپی 7، پاییز 1394)

Acute Myocardial Infarction AMI is one of the leading causes of death throughout the world. Usual methods for detecting AMI are expensive, time-consuming and using blood samples as biological samples. Therefore, creating an ultra-fast, sensitive and non-invasive diagnostic test is necessary. Herein, a novel ultra-sensitive, fluorescent, plasmon-exciton coupling hybrid of a Gold Nano Rod-Quantum Dot RQ -based aptamer nanobiosensor is presented for the detection of human cardiac troponin I cTnI, the golden biomarker of AMI, and a preclinical test is performed with saliva. The binding of the cTnI protein to aptamer leads to a fluorescence enhancement of the plexcitonic hybrid system. The limit of detection of this nanobiosensor is 0.5 fM. It seems this novel nanobiosensor of the RQ plexcitonic hybrid system can open up new opportunities for the design and fabrication of nanobiosensor progress in nanobiotechnology.

In this research, coaxial electrospinning method was used for preparing the core-shell fibers of polycaprolactone PCL and polyvinyl alcohol PVA, and silver nanoparticles were added through the reduction of silver nitrate in core solution before processing. The presence of silver nanoparticles was proved by observing the absorption peak in UV-visible spectroscopy test in the range of 420-430 nm. Antibacterial properties were investigated according to ATCC100 standard by usage of E.coli and S.aureus bacteria on single layer fibers mat of PCL, PVA, PCL containing silver and PVA containing silver, as well as core-shell fibers mat of PVA-Ag/PCL and PCL-Ag/PVA. The results showed that core-shell fibers have strong antibacterial properties like single layer fibers containing silver. Also, adding silver nanoparticles caused a slight enhancement in contact angle or hydrophobicity of the fibers. The water vapor transmission rate test exhibited that WVTR value decreased with the addition of silver and fabricating core-shell fibers while in comparison with commercial wound dressing, this value is more close to human WVTR value.

In the present work, Cu-doped ZnSe Nanocrystals NCs were synthesized by a simple photochemical method. XRD and TEM analysis demonstrated zinc blende phase NCs with an average size of around 3 nm. UV-Vis analysis showed decreasing the band gap of ZnSe NCs from 3.80 to 3.45 eV for 5 to 15 min illumination time. Photoluminescence spectra of ZnSe NCs showed a broad emission with two peaks located at 380 and 490 nm related to excitonic and trap states emission, respectively. For ZnSe:Cu NCs, excitonic emission was decreased and PL intensity of trap states emission increased and for 10 min illumination, excitonic emission quenched completely and trap states emission reached to its maximum value.

In this paper, electron transport in a metal/molecule/metal molecular system Includes biphenyl-dithiol molecule and three-dimensional gold electrodes for three different types of contact geometry, are investigated. The Hamiltonian of the molecule is calculated based on the Hückel method and the current is computed by the non-equilibrium Green’s function method in the framework of Landauer–Büttiker formalism. Transmission coefficient and current-voltage characteristics are calculated for three different geometric structures. The results show that electron transport is strongly affected by quantum interference of electron waves and the geometry of the molecule-electrode interface. The current amplitude for symmetric coupling is larger than two other asymmetric couplings because of the quantum interference effects of the electron waves traveling through the different paths.

Supported copper II on functionalized Fe3O4 magnetic nanoparticles was used as high efficient and magnetically recoverable catalyst for the oxidation of sulfides to sulfoxides and oxidative coupling of thiols into corresponding disulfides using hydrogen peroxide H2O2 as oxidant. An aliphatic and aromatic series of sulfides and thiols including various functional groups was successfully converted into corresponding products. All of products were obtained in good to excellent yields. The magnetic nanocatalyst was characterized by FT-IR spectroscopy, TEM, XRD, SEM, and TGA techniques. Recovery of the catalyst is easily performed via magnetic decantation and reused for several consecutive runs without significant loss of its catalytic efficiency and activity.

We have investigated the behavior of dynamical thermal conductivity of doped biased bilayer graphene for AA-stacking as a function of frequency in the context of tight-binding model Hamiltonian. In this work, it has considered frequency dependence of temperature gradient. Green’s function approach has been implemented to find the behavior of thermal conductivity of bilayer graphene within Kubo linear response theory. Different behaviors have been seen for thermal conductivity due to different frequency. Also thermal conductivity versus bias and temperature has investigated. Dynamical thermal conductivity decreases with chemical potential, bias voltage and temperature, while it has a relative fluctuation with frequency at high bias voltage and high temperature.