Papers by Author: Tijjani Adam

Abstract: Chitosan (CS) is an interesting polysaccharide biopolymer that widely used in the fields of agriculture, horticulture, industry, biomedicine and chemical sensor due to its numerous advantage like non-toxic nature, excellent film forming ability, good mechanical strength, high permeability and cost effectiveness. The chitosan solution (0.05 %) was prepared by dissolving 0.05g chitosan (Sigma corp) in 10 ml of acetic acid (2mol/L). after the is the preparation of preparation of chitosan: A very small amount of chitosan were taken and dissolved in distilled water. The solution was then ultrasonicated for 90 minutes to obtain a homogenized solution. The spectra shows featureless absorption in the 400-800 nm and a sharp absorption peak at 250 nm regions which are similar to the spectra of chitosan in the previous research. The UV-vis spectra of chitosan in at different concentration. The spectra show featureless absorption in the 400-800 nm. A sharp absorption peak at approximately 300 nm. The observed absorption peak in chitosan solution depends on the solution concentration. When the chitosan concentration was less, the peak was not that clearly seen compared to the concentration of 0.05.

Abstract: At a macro scale level, mixing is generally achieved by a turbulent flow, which makes possible of segregating the fluid in small domains, thereby leading to an increase in the contact surface and decrease in the mixing path. At low Reynolds number, the viscous effects dominate inertial effects and a completely laminar flow occurs. In the laminar flow system, fluid streams flow parallel to each other and the velocity at any location within the fluid stream is variant with pressure when boundary conditions are constant and due to the change in surface area–to-volume tension and diffusion, do not simply scale linearly from large to small devices. This makes the use of microfluidic as a mixing device difficult. Thus, the study posed to bridge this gap by created geometrically enhanced Micromixer for homogenous mixing.

Abstract: An in-expensive way of fabricating PDMS microfluidic using room temperature curing process is presented which can be used for both laboratory and commercial scale. The microfluidic was designed using AutoCAD for master mold preparation and subsequently created with SU8 for rapid prototyping process; the micro mixer and the whole mixer were fabricated in less than without using costly fabrication steps. The device profiles were observed for structural integrity and evaluation by dropping two food coloring dyes through the two inlets and collecting the sample at outlet. Flow rate and mixing efficiency were quantitatively measured by analyzing the recorded flow profiles and values of the image collected from the high powered microscope at inlet and outlet locations is fully obtained and will be presented in our next publication

Abstract: The paper reported a study on an effect of the point charge of the bio-interface of a nanowire field biosensor on the conductance of the nanowire, through finite element calculations using COMSOL Multiphysics. A model with 5 layers starting with silicon nanowire of radius 10nm surrounded by a 2-nm oxide layer, and the oxide layer were surrounded by a 5 nm thick functional layer and 2 points charge were considered for this study and last layer is for electrolyte. The results shows that is different voltages with points change is that effected on the conductance of nanowire that is clear from different of potential distribution of point charge.

Abstract: Currently, the potential use of Semiconductor nanowires as parts of future devices has triggered an increased interest in biosensor research. The COMSOL Multiphysics is simulation used that can improve the sensitivity of Bioelectronics to extend their stability and utility. In this paper, we are investigating the effect of DNA concentration of the electrolyte effect biosensor on the conductance of the nanowire through finite element calculations. First, the distribution of the electrostatic has potential in the nanowire due to the DNA concentration. In conclusion of this paper represented DNA that conductance nanowire is affected from surface modification after DNA including on the model.

Abstract: We investigated into report a study biosensor based on silicon into an effect on the dimensions of conductance design and simulation nanowire surface with molecular DNA for sensitivity. In the design nanowire of A biosensor with 3 layers starting with polyisilicon nanowire of radius 8 NM surrounded by a 50-nm electrode layer, and the substrate by a 300nm. COMSOL Multiphysics software used to provide interaction with molecules such as DNA and the distribution of the electrostatic potential in the narrower due to the dimensions, surface nanowire charge was computed using Poisson equation with Boltzmann statistics. In the result of the effect geometry was also studied and the different dimension yield different space charge and the surface charge at interactive site were also investigated and the study demonstrate steps wise identification of all critical parameters for (DNA) attachment with surface nanowires.

Abstract: This paper mainly illustrate regarding the fabrication process of IDE based sensor for bio-molecular detection process. Material that is utilized in this process is zinc oxide due to bio-compability and elevated electrical characteristic. IDE mask is designed by using auto-cad software which tailors for detection of bio substance which is extremely small scale in size. Zinc Oxide material is also used due to presented of nanostructure that can be synthesized through hydrothermal route. Zinc oxide solution is prepared by series of sol-gel process and is coated on the SiO substrate which acts as insulator layer during the lithography process. IDE mask is patterned transfer on sample by using conventional lithography process which the parameters are critically adjusted to ensure that the pattern transfer process occur with minimal defects. The fabricated sensor will be further validated through electrical and morphological characteristic. Capacitance test and impedance test is taken with various pH solution to observe the response of the sensor with different pH values. Keywords: IDE sensor, bio-compability, Zinc Oxide, auto-cad software, sol-gel, SiO substrate, hydrothermal route

Abstract: In the past two decades, COMSOL Multiphysics Software Package have emerged as a powerful tool for simulation, particularly in Nanotechnology and most importantly in biomedical application and various application involving fluid and solid interactions. Compared with conventional component or system design, distinctive advantages of using COMSOL software for design include easy assessing to the significant parameters in various levels of design, higher throughput, process monitoring with lower cost and less time consuming [1,. This review aims to summarize the recent advancements in various approaches in major types of micro fluidic systems simulations, design application of various COMSOL models especially in biomedical applications. The state-of-the-art of past and current approaches of fluid manipulation as well as solid structure design fabrication was also elaborated. Future trends of using COMSOL in nanotechnology, especially in biomedical engineering perspective.

Abstract: A fluid dynamics in a micro channel for analytical chemistry and different aspects of this type of flow for specific application has remained a long-acting problem in the last two decades considering its numerus applications in various fields, thus, Surface tension and wall adhesive forces are often used to transport fluid through micro channels in Micro Electromechanical system devices or to measure the transport and position of small amounts of fluid using micropipettes. Here we took the advantages of wall adhesion and surface tension at the air/fluid interface, fluid rises through the channel and study also calculate the velocity, pressure and shape and position of the fluid surface, the model consist of a capillary channel of radius 50μm and a chamber. The study demonstrated that the fluid freely flown into the chamber 2mm/s without using any external mechanism.

Abstract: In this work, we report the used of Negative Pattern Scheme (NPS) by Electron Microscope Based Electron Beam Lithography (EBL) Technique in connection with scanning electron microscope (SEM) for creating extremely fine nanowires. These patterns have been designed using GDSII Editor and directly transferred on the sample coated with ma-N 2400 Series as the negative tone e-beam resist. The NPS designs having line width of approximately 100 nm are successfully fabricated at our lab. The profile of the nanowire can be precisely controlled by this technique. The optical characterization that is applied to check the nanowires structure using SEM and Atomic Force Microscopy (AFM).