Papers by Keyword: Biomolecule

Abstract: The detection of most serious diseases at early stages is one of the challenging tasks for researchers of nanotechnology. Therefore the current research article is one of the attempts to fabricate highly sensitive and selective micro-gap electrodes at initial level; such micro-gap electrodes will be used in future for inserting biomolecule in between the gap spacing. To transfer the micro-gap design pattern to sample wafer accurately and preciously, micro-gap was initially designed by using AutoCAD software and the design was finally transferred to high sensitive and selective chrome mask. The article demonstrates experimentally an initial strategy for fabrication of micro-gap electrodes at resisting using conventional photolithography technique coupled with the wet etching process. The structure morphology was characterized using high power and scanning electron microscope namely (HPM and SEM).

Abstract: In this paper, charge-modulated field effect transistor based detection circuit is presented for the purpose of electrical detection of DNA hybridization. The readout circuit consists of a drain follower and a compensated differential amplifier. It is able to achieve a voltage gain of 56.94 dB in the frequency range up to 6.79 kHz using 0.18μm Silterra CMOS process. The compensation technique is used in the detection circuit in order to improve the phase margin to 52.66^o. The proposed potentiometric biosensor eliminates the need for a reference electrode which can offer great potential for miniaturized sensor array that would enable a massive parallel detection of DNA assay.

Abstract: Fabrication techniques for Metal-molecule-metal junction electrodes suitable to study electron tunneling through metal junctions are reviewed. The applications of current technologies such as mechanical break junction, electromigration, shadow mask lithography, focused ion beam deposition, chemical and electrochemical plating, electron-beam lithography, in fabricating vacant junction electrodes are briefly described. For biomolecular sensing applications, the size of the junction electrodes must be small enough to allow the biomolecule inserted into the junction space to connect both leads to keep the molecules in a relaxed and undistorted state. A significant advantage of using Metal-molecule-metal junction electrodes devices is that the junction can be characterized with and without the molecule in place. Any electrical artifacts introduced by the electrode fabrication process are more easily deconvoluted from the intrinsic properties of the molecule.

Abstract: This study is about the underlying conjugation mechanism between carbon nanotube and biomolecule by molecular dynamics. In order to know about the conjugation mechanism between carbon nanotube and biomolecule, molecular dynamics simulation between carbon nanotube and water molecules was taken first and then molecular dynamics simulation between biomolecules and water molecules was taken. At simulation between carbon nanotube and water molecules, kinetic energy and potential energy became decreased with time and it means that the distance between carbon nanotube and water molecules becomes distant with time by van der Waals force and hydrophobic force. Simulation results between biomolecules and water molecules are also same as the results of carbon nanotube and water molecules simulation. From these two simulations, the conjugation mechanism between carbon nanotube and biomolecules can be predicted. Also, from simulation results between carbon nanotube and biomolecules, the distance between carbon nanotube and biomolecules becames close and it supports previous two simulation results. From these results, we can know that biomolecules enter into the carbon nanotube's cavity because of van der Waals force and hydrophobic force.

Abstract: We have attempted to realize new biomolecular-inorganic nanohybrids with two different functions, one from inorganic moiety and the other from biological one. Recently we were quite successful in demonstrating that a two-dimensional inorganic compound like layered double hydroxide (LDH) can be used as gene or drug delivery carriers. Such inorganic vectors are completely new and different from conventionally developed ones such as viral-based, naked, and cationic liposomes, those which are limited in certain cases of applications due to their toxicity, immunogenecity, poor integration, and etc. But the mentioned problems can be overcome by synthesizing inorganic vectors properly with non-toxic metal ions having biological compatibility. Since LDHs with positive layer charge have an anion exchange capacity, functional biomolecules with a negative charge can be intercalated into hydroxide layers of LDH by a simple ion-exchange reaction to form a bio-LDH nanohybrid. We also found that the hydroxide layers of LDHs could protect the intercalated molecules very efficiently. If necessary, inorganic materials, as reservoir and delivery carrier, can be intentionally removed by dissolving it in an acidic which offer a way of recovering the encapsulated biomolecules. The possible roles of inorganic lattice as the gene and drug delivery carrier will be shown by demonstrating the cellular uptake experiments of FITC, fluorophore, with laser scanning confocal fluorescence microscopy. A