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Microtechnologies in Medicine & Biology 2nd Annual International IEEE-EMB Special Topic Conference on

Date 2-4 May 2002

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Displaying Results 1 - 25 of 121
  • 2nd Annual International IEEE-EMBS Special Topic Conference on Microtechnologies in Medicine and Biology. Proceedings (Cat. No.02EX578)

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    Freely Available from IEEE
  • Author index

    Page(s): 569 - 574
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    Freely Available from IEEE
  • Keyword index

    Page(s): 575 - 579
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    Freely Available from IEEE
  • Individually addressable planar patch clamp array

    Page(s): 71 - 75
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (747 KB) |  | HTML iconHTML  

    We present a new planar, silicon-based patch clamp array. Each patch site is vertically oriented, which allows simultaneous use of scanning probe, optical, or fluorescent detection technologies. Each microfabricated patch site is also connected to its own fluidic channel so that the array can be used for parallel screening of cells or analysis of tethered lipid membranes or vesicles that express the proteins of interest. A single unit, fully three-dimensional ring-shaped patch clamp recording device has been designed and fabricated View full abstract»

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  • Simulation of electrode impedance and current densities near an atherosclerotic lesion

    Page(s): 57 - 61
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    A four-point electrode measuring impedance in the vicinity of an atherosclerotic lesion was modeled using FEM software. The simulation modeled the electrodes as being attached to an angioplasty balloon in a coronary artery. Impedance was calculated when the "balloon" was uninflated (not in contact with the lesion) and inflated (in contact with the lesion). Additionally, different lesion types (Va and Vb, as defined by the American Heart Association) and the effects of the low-conductivity calcium layer were considered. Results showed that the real component of the impedance was much higher when the electrodes were in contact with lesion. When the electrodes were not in contact with the lesion, the real component was low. Also, when the electrodes were in direct physical contact with the lesion, the difference between various lesion morphologies could be seen by observing the differences in the imaginary and phase component of the impedance. As a consequence of these simulations, it appears plausible that four-point electrodes mounted to an angioplasty balloon may be useful in determining whether a balloon has made contact with a lesion, and in characterizing that lesion View full abstract»

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  • Development of micro Hemocytometer for human erythrocyte analysis for the early detection of cancer

    Page(s): 496 - 499
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    The relation between erythrocyte deformability and cancer has been proved in medical fields, but it is very difficult to systemize and commercialize the traditional schemes for erythrocyte deformability assessment. In this work, a desk-top type RBC Hemocytometer system with PDMS microchip has been developed for the assessment. Macrochannels with microfiltering structure in the microchip make the erythrocyte deformed, and with an UV optical array system and C language based image processing software, filter-pass-shape and filter-pass-velocity of erythrocytes are sequentially analyzed. In the comparative studies with blood from cancerous patients and control blood, we could obtain statistically acceptable data that can distinguish cancerous from control regardless of the cancer infected regions. To enhance the performance of the system, comparative studies changing the materials of the chip (silicon-glass, PDMS and PMMA) and sectional surface characteristics control have been accomplished with notable results. This RBC Hemocytometer system can be applied as a practical diagnostic apparatus in early detection of cancer View full abstract»

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  • Biophotonic MEMS for single molecule detection and manipulation

    Page(s): 363 - 368
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    The development of biophotonic MEMS for single molecule detection (SMD), manipulation and optical trapping is presented. Integrated cyclic SixNy microfluidic devices with microelectrodes are fabricated with surface micromachining techniques. Microfluidic channels in the optical windows consist of just SixNy membrane without substrates. Capability of SMD, manipulation and optical trapping are demonstrated with the SixNy membrane channels. Such a device can be used in high throughput screening bioassay chips, which require multiplexed processing, SMD, and manipulation capability. Compared with earlier works on microfluidic devices formed by bonding two-glass substrates or polymers, our multiplexed design has attractive features such as bondless nano- and microfluidic channels, low transmission loss, and high stability to temperature and chemicals. The advanced biophotonic MEMS will have characterization and multiple manipulation tools for high-resolution spectroscopic analysis, robotic controls, and microscale lab automations on a chip View full abstract»

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  • Polymeric trapezoidal microelectrospray emitter integrated with a microfluidic chip

    Page(s): 62 - 65
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    We have demonstrated an electrospray of fluid from a tip made from a shaped thin polymer tip bonded to a microfluidic channel. A trapezoidal electrospray emitter was fabricated using lithography and plasma etching. This was integrated with a channel and used for electrospray ionization of small molecules. A lithographically produced silicon master was used to emboss a microfluidic channel in a cyclo olefin substrate. The electrospray emitter was sandwiched between the two plastic pieces at the exit of the microfluidic channel and thermally bonded. The microfluidic channel dimensions were 40 μm wide, 20 μm deep and 2.5 cm long. One end of channel was directly connected to the electrospray emitter and another end of channel was connected to the silica capillary tubing which was connected to an external syringe pump. 70/30 methanol/DI water with 1% acetic acid was used for testing the spraying characteristics. A grounded aluminum plate was placed 0.6 cm from the electrospray emitter and 2500 volts applied at the reservoir. A Taylor cone was formed on the trapezoid electrospray emitter film. A stable liquid flow of 300 nl/minute was created by the syringe pump for supplying liquid to the electrospray emitter and to maintain a constant spray. 40 nA of total ion current was measured by a picoammeter for 40 minutes View full abstract»

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  • Microstructural and functional aspects of water transfer under tension in plants

    Page(s): 453 - 457
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    In plants, liquid water coming from the soil is conducted within a network of very fine capillaries (conducting elements) where cavitation occurs. In this article we describe the main physiological and physical phenomena, like cavitation, involved in ascent of sap in trees View full abstract»

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  • Gravity-driven microhydrodynamics-based cell sorter (microHYCS) for rapid, inexpensive, and efficient cell separation and size-profiling

    Page(s): 466 - 469
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    Describes a new type of gravity-driven polymeric microfluidic cell sorter developed for low-power, low-cost, and rapid cell separation. The device takes advantage of size-based differential migration of cells/particles in flows where widening of flow streamlines amplifies the separation between sample particles. We studied the migration and separation of polystyrene microbeads, red blood cells, and perfluorocarbon droplets used for ultrasound imaging and therapy having different sizes in the novel cell sorter. Compared to other conventional cell separation systems, microHYCS reduces power and cost requirements, and is advantageous for the development of easy-to-use sample separation and diagnostics tools View full abstract»

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  • MAPS: the micro action potential scanner

    Page(s): 232 - 236
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    A new high-resolution neural probe, the micro action potential scanner (MAPS), is proposed. The MAPS is designed for simultaneous recording from many cells in a single neural network, a challenging task using conventional neural probes. Conjectures are made about the MAPS' potential to record from more single cells from a smaller area than microelectrode arrays due to the MAPS' higher spatial resolution. The MAPS gains its high resolution by its ability to scan an area of neural tissue. Scanning is made possible by the novel use of a p-n junction View full abstract»

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  • Intelligent monitoring systems: smart room for patient's suffering from somnambulism

    Page(s): 326 - 331
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (519 KB) |  | HTML iconHTML  

    Somnambulism is a sleep disorder characterized by walking or other activity while seemingly still asleep. The sleep walking activity may include simply sitting up and appearing awake while actually asleep, getting up and walking around, or complex activities such as moving furniture, going to the bathroom, dressing and undressing, and similar activities. Someone might even drive a car while actually asleep. For the simplicity and convenience of the project we have restricted our occupants environment to a single room, which we call a "smart room". We consider that the user is an adult who is suffering from somnambulism. Our intention is to prevent the occupant to move out of his room as well as monitor his movement after he's gone to bed, if the patient seems to move out then immediately inform the caretaker about it as well as try and wake up the patient from the sleep in a modest way so that it doesn't come up as a shock to him, all this needs to be done by a smart responsive system which would be embedded in the patients room. This system is designed to work on the principles of assistive technology (technology used to assist caretakers) View full abstract»

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  • Acousto-electromagnetic properties of human dentin

    Page(s): 189 - 192
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    Scanning acoustic microscopy (SAM) near-field scanning microwave microscopy (NSMM), micro-Raman spectroscopy (μRS), atomic force microscopy (AFM), and scanning electron microscopy (SEM) were used to study dentin, its demineralization, and its interface and bonding with epoxy and adhesives. SAM yielded information regarding micro-mechanical properties of dentin and its interface while μRS provided information regarding the curing state of the epoxy and presence of contaminants at the dentin/epoxy interface. NSMM, a new technique developed in our laboratory, provided information regarding the interface conductivity and permittivity that are related to density, presence of ionic species and among other factors. Simultaneously performed with AFM, NSMM provided interesting complementary information regarding dentin and epoxy system. Owing to the large penetration depth of its sensing signal in most biological materials, NSMM is capable of imaging sub-surface non-uniformity the scanned surfaces. We report preliminary findings indicating complementary and corroborating natures of SAM, NSMM, μRS, and AFM View full abstract»

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  • A low-voltage electrostatically actuated MEMS scanner for in vivo biomedical imaging

    Page(s): 205 - 207
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    With the inherent advantages of micromachining technologies such as small size, small mass, low cost, low power consumption and high reliability, there will be radical changes to biomedical devices and how clinical diagnoses are made. One of the most promising applications of microtechnologies is in the biomedical field. This paper presents a low-voltage high-torque MEMS 2D scanner well suited for in vivo biomedical imaging View full abstract»

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  • The Large Scale Digital Cell Analysis System and its use in the quantitative analysis of cell populations

    Page(s): 470 - 475
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (699 KB) |  | HTML iconHTML  

    The Large Scale Digital Cell Analysis System (LSDCAS) was designed to analyze large numbers of cells under a variety of experimental conditions. LSDCAS is an automated microscope system capable of monitoring of the order of 1000 microscope fields over time intervals of up to one month. Although LSDCAS was originally designed to study stress-induced mitotic catastrophe, current efforts aim to provide imaging and data modeling/visualization technologies that will be useful in many areas of biological research. Several collaborative projects with University of Iowa researchers are underway involving the study of alterations in cell motility associated with metastasis; determination of the fate of cells which overproduce pro-oxidants, as well as the development of software to automatically determine the mode of cell death following exposure to cytotoxic agents. Ongoing extension of the capabilities of LSDCAS using image segmentation techniques based upon active appearance models will allow for the measurement of a variety of cellular endpoints. This report details our ongoing studies using LSDCAS; in particular its use in the quantitation of cell motility is described. Following these preliminary analyses, the report ends with a discussion of current development of LSDCAS to provide real-time fluorescence-based analysis of pro-oxidant production in cultured cells View full abstract»

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  • A continuous peristaltic micropump using magnetic fluid

    Page(s): 509 - 513
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    Introduces innovative results for the enhanced magnetic fluid (MF) microactuator. A reduced response time and increased diaphragm deflection are derived from a MF (N304) and the changed number of corrugations on the parylene diaphragm is optimized by FE analysis applied to the existing model. This paper also proposes a new design of peristaltic MF micropump based on the previous experiment data of the existing MF actuator for the purpose of application of 'Lab on a chip' which is the core technology of medical and biological fields. In this device, magnetic fluids are gathered in the round-shaped or polygon-shaped channels by magnetic force, which is applied by the external magnet. The concentrated MF lump can deform the parylene diaphragm and then the deformed diaphragm pushes the fluids in another microchannel View full abstract»

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  • Characterization of protein interaction with tunable microfabricated hydrogels

    Page(s): 400 - 404
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    Work was completed to quantify biomolecule diffusion into photopolymerized hydrogels of varying crosslinking densities. Fluorescence recovery after photobleaching (FRAP) and gray-scale fluorescence intensity photographs were used in the analysis. For diffusion rates, three proteins were examined: bovine serum albumin, lysozyme, and IgG1. The diffusion in the hydrogels appears to be linearly related to the swelling ratio of the hydrogel and dependent on the hydrodynamic radius of the diffusant once critical crosslinking density has been reached. Higher swelling ratio gels exhibit a larger degree of protein penetration and "storage" in the gel matrix. We conclude that the use of these methods to characterize engineering materials with biomolecules will contribute to a better understanding and better design of sensors and actuators in a biological environment View full abstract»

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  • Design and fabrication of a MEMS filter bank for hearing aids applications

    Page(s): 352 - 355
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (593 KB) |  | HTML iconHTML  

    A novel MEMS filter bank was developed for hearing aids application. It directly processes the sound signals by separating the sound into specific frequency bands. Therefore, the filter bank can replace some function of the microphone and the processor within the modern hearing aids. Such a MEMS filter bank works as a passive component, and it has the advantages of lower energy consumption and without computation time. Combining with its excellent aging and thermal stability characteristics, the novel MEMS filter bank will be a potential device for effective sound signal processing in modern hearing aids. The paper shows the fabrication process of the novel MEMS filter bank. Our preliminary results show that the device dimensions of the filter bank are about millimeter level for the low operating frequency requirement, 100 Hz to 10000 Hz. The devices are then apparent bending by residual stress with low stress silicon nitride film View full abstract»

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  • Culturing of neurons in microfluidic arrays

    Page(s): 160 - 163
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    The ability to culture cells on microchips, containing arrays of micro-chambers, is becoming an important diagnostic tool to the biomedical researcher. In this work different neural cell types are cultured in microfluidic arrays made from glass and PDMS substrates.. The microfluidic arrays are made using photolithographically patterned two-layer SU-8 mold and transferred to the PDMS. This allows the creation of interconnected microchambers, which permit physically isolated cells to form axons in preferential directions. The culturing of several different neural cell types was performed using PC-12, P19 and primary culture neural cells. The viability of the cells and integration with microelectrode arrays was tested View full abstract»

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  • Flow characteristics of hydrophilic/hydrophobic capillaries considering surface tension

    Page(s): 560 - 564
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    The surface tension driven flow characteristics should be considered for the initial priming of microfluidic chips with the hydrophilic or hydrophobic surfaces. The hydrophobic capillaries have been prepared by exposing the hydrophilic glass capillaries to pure hexadecane and an octadecyltrichlorosilane (OTS) solution. The displacements and velocities of fluid menisci in two kinds of tubes are measured while changing the inlet pressures. Numerical solutions of fluidic equation show a comparable agreement with experimental results when considering the surface tension. It is also shown that partially coated hydrophobic region of capillary could be used as a passive valve View full abstract»

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  • Silicon neural recording arrays with on-chip electronics for in-vivo data acquisition

    Page(s): 237 - 240
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (581 KB) |  | HTML iconHTML  

    This paper describes a 64 site, 8 channel silicon microelectrode for single-unit neural recording. The probe features integrated CMOS circuitry for electronic positioning of the active recording sites with respect to active neurons. On-chip capacitively coupled pre-amplifiers eliminate the DC baseline polarization of the electrode while providing a per channel gain of 1000. Time-division multiplexing circuitry is provided for sampling the 8 active channels onto one data lead. The on-chip circuitry consumes 834 μW of power from ±1.5 V supplies and occupies 4.34 mm2 of die area. The probe is fabricated using an 18 mask, single-sided, micromachined CMOS process with a 3 μm minimum feature size View full abstract»

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  • Mechanical characterization of surface micromachined microneedle array

    Page(s): 94 - 98
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    This paper will report on the mechanical characterization of hollow metallic microneedles. The characterization will include the affects of design variations on the buckling and penetration force of these microneedles, and on the fluid flow characteristics. Needles of five different tip geometry and three different taper angles were designed. The taper angle varies between 15° and 30°. The lengths of the needle shaft tested were 500 μm, 1000 μm and 1500 μm respectively. Microneedles were fabricated using an extension of the work reported earlier. A simple horizontal loading set up consisting of a load cell and a micromanipulator was designed. A rigid orthogonal surface was used in order to study the buckling force, while a mechanically "skin-like" material was used to determine the penetration force. The buckling force was found to vary between 54 gF and 100 gF for needles with shaft lengths of 1500 and 500 μm, respectively. The penetration force was found to be independent of shaft length and was approximately 8 gF. While the needle tips with 15° taper angle failed, the needles with 20° taper angle performed better but experienced a 50% tip failure rate. The flow rate of the microneedles was characterized over a range of 0 - 100 psi using distilled water and air as the fluid media View full abstract»

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  • A novel microfabricated device measures a large fraction of hormone release from individual-cells with high time resolution

    Page(s): 481 - 484
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    Single-cell assays of hormone or neurotransmitter secretion have applications in cell-based biosensor development, high-throughput screening of drugs and basic science investigations. We are using microsystems technology to make electrochemical electrodes in picoliter-size wells for measuring catecholamine release from. individual cells. By making the well-electrode only slightly larger than the cell, high sensitivity and time resolution are achieved. The electrode can detect "spikes" of oxidative current corresponding to the release of individual catecholamine-containing vesicles from bovine adrenal chromaffin cells with millisecond time resolution. In, addition, we have simultaneously used whole-cell patch clamp recording to estimate that more than 60% of catecholamine released from the cell is captured by the well-electrode View full abstract»

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  • Nanometer-scale antibody patterning for directed eosinophil cell immobilization and stimulation

    Page(s): 115 - 119
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    Antibodies (Ab) are patterned at nanoscale precision for the precise immobilization and stimulation of immune cells. We demonstrate that the antigen bovine serum albumin (BSA) can be patterned on silicon using a photolithographically patterned polymer lift-off technique. The nanoscale pattern is realized as the polymer is mechanically peeled away in one contiguous piece in aqueous solution. Anti-BSA Ab are bound specifically to BSA to create a pattern of oriented Ab that provides a surface for eosinophil immobilization and degranulation. The patterns ranged from 0.36 μm2 to 4,489 μm2, appropriate dimensions for the 10-14 μm diameter eosinophil cells. This method provides a new technique for immobilizing cells onto nano and micrometer scale patterns for analyzing cellular biochemical cascade events such as degranulation and studying cellular morphological changes in response to defined nanoscale antigenic stimulus View full abstract»

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  • Mechanical assembly of a microelectrode array for use in a wireless intracortical recording device

    Page(s): 269 - 272
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    Fabrication of a microelectrode array assembly for neural activity recording is described. The assembly forms the mechanical front-end of the telemetric electrode array system, a wireless intracortical recording device designed for motor cortex studies in nonhuman primates. The electrodes are manufactured by wire electrical discharge machining solid titanium. They are then secured in a polyimide substrate. A flexible printed circuit board connector cable connects the array structure to the electrical frontend. Parylene and platinum are used as the encapsulation materials. Results from the implantation of a prototype microelectrode array assembly are discussed View full abstract»

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