chapter
This paper presents unprecedented accomplishments toward unidirectional guidance of cellular migration via durotaxis-based microtopography. In contrast to previous efforts, micropost arrays of varying anisotropy (muPVAs) optimize unidirectional control of cell migration through dual axis durotaxis cues which restrict movement in the lateral direction in addition to promoting migration in the direction...
chapter
Here we present a novel signal processing technique for a square wave thermally-modulated carbon black/polymer composite chemoresistor. The technique consists of only two mathematical operations: summing the off-transient and on-transient conductance signals; and subtracting the steady-state conductance signal. A single carbon black/polyvinylpyrrolidone composite chemo -resistor was fabricated and...
chapter
In this paper, we show that the chemical sensing responses of organic thin film transistors (OTFTs) based on nanostructured regioregular polythiophene are strongly dependent upon the gate biasing field and the operation mode. With different applied gate voltages the source-drain current response can be different both in sign and magnitude for the same analyte. Using swept gate voltages, sensors show...
chapter
This paper presents the optimization of a micro gas preconcentrator applied to environmental monitoring. Different types of adsorbent materials introduced in silicon microchannels with various designs have been investigated and a special focus has been dedicated to the modes of operation of the preconcentrator. The optimization of the device and its operation were driven by its future application...
chapter
Nanocomposite elastomer is an exciting, emerging class of materials for polymer MEMS sensors and actuators . It is made by mixing electrically conducting particles (e.g., carbon nanotubes) in regular, nonconducting elastomer (e.g., PDMS) beyond percolation limit. The bulk resistance of the polymer is a function of particle doping concentration and other parameters (e.g., applied stress). The electrical...
chapter
We report the development of a novel 3-terminal single element piezoresistor for ultra-miniature pressure sensor applications and compare its performance to that of a traditional half Wheatstone bridge design. The pressure sensors reported here are 0.69-French in size (1F= 333 mum) and are designed and batch-fabricated using SOI (silicon on insulator) and DRIE (deep reactive ion etching) technologies...
chapter
The concept of MEMS sensors directly fabricated on a ceramic substrate, which can be used for a package of end product, was proposed. A micro accelerometer utilizing a fringe capacitance formed in a ferroelectric substrate was focused on. For this sensor, in stead of a previously used bulk PZT plate, a screen-printed BaTiO3 (BTO) film on an alumina substrate was employed in this study. A screen-printing...
chapter
We report on a prototype endoscope with tunable-focus liquid microlenses actuated through infrared (IR) light integrated at its distal end. Tunable-focus microlenses scanning the areas of interest with minimal movements of the scopes themselves would greatly advance endoscopy. Multiple IR light-responsive hydrogel posts were used to tune the focal length of the microlens, which were formed by a curved...
chapter
Ultra high aspect ratio microelectrodes are designed and fabricated to record and stimulate neural signals from deeper areas of the brain and nerves and also to provide a new research tool to the neuroscience community. We present a fabrication process to build ultra high aspect ratio silicon based microelectrode arrays for the neural applications. The mu-wire electrical discharge machining (mu-WEDM)...
chapter
Novel unobstructing magnetic microactuators have been designed, fabricated, and tested for use as devices to prevent flow obstruction in implantable catheters. The initial target application is hydrocephalus, which is a neurological disease (commonly known as the ldquowater on the brainrdquo) that often requires long-term implantation of a shunt system to divert excess cerebrospinal fluid from the...
chapter
Growing interest in assessing the reliability of microelectromechanical systems has created a need for the development of microinstruments to interrogate MEMS behavior under diverse conditions. This paper describes the design and testing of a microinstrument for in-situ reliability studies of contacting surfaces in MEMS. Time-dependent changes in the structure, chemistry and electrical properties...
chapter
This paper reports an innovative contactless MEMS-based microresonator actuated by an external time-varying magnetic field. The actuation principle is based on the interaction between the eddy currents and the magnetic field generated by an external inductor driven by a sinusoidal current; the system response is sensed via an inductive pick-up based on a high permeability material (100-mum of diameter)...
chapter
This paper presents the design, fabrication and application of a highly integrated closed loop MEMS system for an active control of aerodynamic flow instabilities across airfoils. A special piezo-polymercomposite (PPC) technology was used for the fabrication of powerful piezo-microactuators that were integrated with hotwire flow sensors and a digital control system. This work shows first wind tunnel...
chapter
We propose a method for attaching flagella to a selected region of a micro-object. We separated the flagella of unicellular algae Chlamydomonas from their body and reactivate them by adding adenosine triphosphate (ATP). We fixed them on a specific region of micro-scale beads using a device that has a perforated Parylene sheet separating a flagella solution from a no-flagella one. We have succeeded...
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This paper reports the fabrication technique of electron micro-optics using silicon deep reactive ion etching. Stacked 120-mum-thick three silicon wafers stacked with cavities using patterned glass substrates are etched by ldquoa direct cavity through etching techniquerdquo. An array of the electron micro-optics consisted of three electrodes can be fabricated by one-mask process without alignment...
chapter
This paper proposes a new valve-less pump with cross-junction channels and integrated hotwires. The pump was actuated by PZT diaphragm to create a gas jet flow for fluidic application. The design and simulation are based on transient fluidic analysis with experimental result of PZT diaphragm so that features of micropump is predicted with high reliability. Two designs of the pumps with different nozzles...
chapter
This paper presents a digital mirror for tunable laser wavelength selection using microelectromechanical systems (MEMS) technology. The digital mirror which has discrete reflection spectrum is totally different compared to the current broadband mirrors MEMS tunable lasers . The reflection of the digital mirror can be tuned by digital pumping signals which promise fast output wavelength switching....
chapter
We present the first multimodal Parylene-based biomimetic platform with the ability to measure tactile forces while simultaneously enabling active stimulation/recording of neural tissue via movable microelectrodes. A liquid-filled microchamber encapsulating interdigitated microelectrodes performs the dual functions of actuation and tactile sensing. The electrodes are impedance-based tactile sensing...
chapter
In vivo biomedical studies using animals can provide high similarity to the physiological conditions in humans. However, it is difficult to observe the molecular processes in the whole animals. On the contrary, in vitro studies could control the environmental factors in experiments but usually are difficult to reflect the complex physiological responses existing in vivo. In this paper, we report our...
chapter
This paper reports a two-phase mini-column separator that depletes immunoglobulin G (IgG) and separates alpha-fetoProtein (AFP) and fibrinogen. A mixture of IgG, fibrinogen, and AFP goes through the two-phase separator, where IgG is depleted by an affinity mini-column using Protein A/G agarose beads in the first phase. In the second phase, AFP is separated from fibrinogen by size exclusion chromatography...
