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Engineers have long envisioned that a handheld portable blood diagnosis device would be able to give an accurate measurement of chemical content based on a very small sample in the shortest time possible. One of the immediate applications of such device is the point of care (POC) diagnosis system, whereby a single drop of human blood would determine his health status. However, a major technical challenge...
Most clinical chemistry tests are performed on cell-free serum or plasma. Therefore micro assay devices for blood tests require integrated on-chip microfluidics for separation of plasma or serum from blood. This is achieved by a new blood separation technique based on a microchannel bend structure developed within the collaborative microtele-biochip (/spl mu/TBC) project co-funded by the German Ministry...
A clamp-and-ratchet microstructure based on poly crystalline silicon (polysilicon) microelectromechanical systems (MEMS) technology has been designed to exert mechanical tension along radial glial processes between groups of neural stem cells to study the effect of tension on cerebral cortex neurogenesis. FEA analysis shows that the design should not fail under expected loading conditions. Preliminary...
This work describes the initial experimental setup and results involving the percentage cell lysis in SWLA-2 murine hybridomas produced by AC electric field pulses of varying amplitudes and pulse widths. Cells were cultured and separate samples examined at 24 hours. The frequency, pulse width and peak-to-peak voltage were varied. AC electric fields producing at least 1 V across the cell membrane appear...
A novel screening platform for the screening and optimization of protein crystallization is reported. Here we present two key experiments to generate protein crystallization phase diagrams. One is to precisely generate spatial gradient droplet arrays; the other is to trap and identify each droplet in place in order to carry out temporal and spatial analysis. The generated concentration and volume...
Fluorescent biosensors can be highly specific and sensitive, and may be engineered as implantable devices for metabolic monitoring. Commonly-used systems for glucose monitoring based on resonance energy transfer (RET) and competitive binding involve Concanavalin A (Con A), which is known to be toxic, and has problems of aggregation and irreversible binding. This work presents an improved RET assay...
An increasing complexity of microfluidic chips and systems used for biochemical assay applications calls for the development of new strategies towards their functionality integration in order to achieve optimum assay performance. Approaches to an integration of microfluidic chips into diagnostic fluidic systems are reviewed with the emphasis on the selection of assay application, integration scheme,...
When live endothelial cells imaged using atomic force microscopy (AFM), distortion of the cell shape could be caused by the interaction between the probe and cell membrane, which depends on the force and the scanning speed used. In this study, a shape recovering method was developed. Two forces were considered in the method: the vertical and the lateral force of the tip exerted on the cell membrane...
In this study, we developed a method that target cells in suspension can be separated by combining magnetic force and gravitation force. Since the newly developed method involves a separating process of a droplet containing nontarget cells in suspension by applying magnetic force to separate target cells, we called it droplet-based magnetic activated cell sorting (dMACS). To demonstrate the efficiency...
Planar 2-dimensional dielectrophoresis electrode geometries are limited in only being capable of handling fluid volumes ranging from picolitres to hundreds of microliters per hour. A 3-dimensional electrode system has been developed capable of handling significantly larger volumes of fluid. Using finite element modeling the electric field distribution within various bore sizes was realized. From these...
A methodology is presented for simultaneous mechanical testing and atomic force microscopy imaging of single collagen fibrils under load. This method holds the promise for determining single-fibril modulus and strength in various experimental preparations. Examples of this utility include characterization of deformation and failure modes of naturally occurring and engineered structural proteins. Additional...
Several novel devices under development in our laboratories to ultimately realize a micro robotic system for single cell nanoscale probing, injection, imaging and surgery is described in this paper. Thus far, we have 1) developed MEMS polymer grippers that can be actuated under water with very large deflection and are capable of gripping 500/spl mu/m embryonic cells in water with /spl sim/2 V input;...
This work presents the basic design and tests of a device designed for detecting the contact between a microinjection pipette and cell membrane. The device facilitates the automation of the microinjection procedure of living adherent cells. The measurement of the contact is based on measuring the resistance of the pipette. Breakage and clogging of the pipette can be detected with the same measurement.
Thermal ablation has been investigated as a treatment for a variety of cancers. Heat treatments have not gained large-scale clinical acceptance due to inconsistencies in controlling heat deposition in vivo and the lack of precise temperature measurement. Interstitial ultrasound provide a good method of controlling the radial depth of a thermal lesion and the applicator designs evaluated in this study...
A detailed and a simplified model of a lesioning electrode was made using the finite element method. 15 simulations of the lesioning procedure were performed for each model and the resulting lesion volumes were compared in order to investigate if the simplified model is adequate. The simplified model resulted in a very slight overestimation of the volume compared to the detailed model. It was thus...
Calibration of lithotripters is important for proper therapeutic treatment of the patients suffering with the presence of the stones in the kidney. Hence, a new semiconductor lithotripsy sensor is developed here to study the optimum performance of the kidney stone disintegrators. The present lithotripsy sensor has four-arm Wheatstone bridge sensor chip having associated electronics of signal conditioning,...
A new transducer system has been developed for in vivo measurement of pressure on spinal growth plates. A model has been previously proposed for correcting spinal deformities with a staple-like implant, and this sensor will be used in vivo to quantify the pressure that alters growth in this new model of deformity and treatment. The pressure sensor die was 0.65 mm/sup 3/ and the overall packaged sensor...
This work presents an experimental validation study of four major algorithms for estimating the instantaneous helical axis parameters for rigid-body motion. The angular velocity vector was first estimated from landmarks trajectories by four methods and compared to the measured one by a miniature triaxial gyroscope. It was found that the four methods are equivalent, that the estimated angular velocity...
Utilization of the changes in skin resistance during reverse iontophoresis is proposed to detect severe perspiration as well as to correct the glucose estimation. Developed system consists of the amperometric biosensor unit, the electrode unit, a constant current driver circuit and a microcontroller-based control. Performance of the developed system was evaluated by the in-vitro skin model which was...
Virtual reality (VR) is a promising technology in biomedical engineering, but at the same time enlarges another problem called cybersickness. Aiming at suppression of cybersicknes, we are investigating the influences of vection-induced images on the autonomic regulation quantitatively. We used the motion vectors to quantify image scenes and measured electrocardiogram, blood pressure, and respiration...
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