Lung-on-a-chip (LoC) models hold the potential to rapidly change landscape for pulmonary drug screening and therapy, giving patients more advanced less invasive treatment options. Understanding absorption in these microphysiological systems, modeling lung-blood barrier is essential increasing role of organ-on-a-chip technology development. In this work, epithelial/endothelial tissue interfaces were established microfluidic bilayer devices transwells, with porous membranes, permeability...

Lack of adequate models significantly hinders advances in prostate cancer treatment, where resistance to androgen-deprivation therapies and bone metastasis remain as major challenges. Current vitro fail faithfully mimic the complex physiology. In vivo animal can shed light on oncogenes involved development progression; however, gland is fundamentally different from that human, underlying genetic mechanisms are different. To address this problem, we developed first microfluidic human...

Micromachining technology was utilized to fabricate a transparent microchannel heat-sink system by bonding glass silicon wafer. The micro heat sink consisted of array, heater, and temperature sensor array. This integrated microsystem allowed simultaneous qualitative visualizations the flow pattern within microchannels quantitative measurements distributions, rates, input power levels. Boiling curves as function were established. No boiling plateau observed in curves, consistent with our...

A unique technique of mask-less and self-aligned silicon etch between bonded wafers was developed applied to fabricate a microchannel heat sink integrated with heater an array temperature sensors. The allowed the formation self-stopped etching grooves wafers. device, consisting distributed microsensors, direct measurements for different levels power dissipation under forced convection using either nitrogen or water as working fluids. measured distributions are used characterize micro...

A nonlinear equation based on the hydrodynamic equations is solved analytically using perturbation expansions to calculate flow field of a steady isothermal, compressible and laminar gas in either circular or planar microchannel. The solution takes into account slip-flow effects explicitly by utilizing classical velocity-slip boundary condition, assuming properties are known. Consistent provide not only cross-stream but also streamwise evolution various parameters interest, such as pressure,...

Attachment, deformation and detachment of N-cadherin expressing prostate breast cancer cell lines in a functionalized microchannel under hydrodynamic loading have been studied. antibodies are immobilized on the surface to capture target cells, PC3N MDA-MB-231-N, from homogeneous suspension. Although difficult, significant fraction moving cells can be captured low flow rate. More than 90% after certain incubation time no condition. The mechanical response field is investigated and,...

We present a novel microsystem-based assay to assess and quantify pollen tube behavior in response pistil tissues. During plant reproduction, signals from female tissues (pistils) guide the sperm-carrying egg cell achieve fertilization initiate seed development. Existing guidance bioassays are performed an isotropically diffusive environment (for example, semi vivo petri dishes) instead of anisotropically conditions required characterize signal gradients. Lack sensitive bioassay has...

Circulating tumor cells (CTCs) are the principal vehicle for spread of non-hematologic cancer disease from a primary tumor, involving extravasation CTCs across blood vessel walls, to form secondary tumors in remote organs. Herein, polydimethylsiloxane-based microfluidic system is developed and characterized vitro systematic studies organ-specific CTCs. The recapitulates two major aspects vivo microenvironment: local signaling chemokine gradients with an endothelial monolayer. parameters...

A new technology to pattern surface charges, either negatively or positively, using a standard photolithography process is introduced. positively charged poly(allylamine hydrochloride) (PAH) layer coated onto silicon oxide by electrostatic self-assembly (ESA). Combined with in lift-off-based process, several different charge patterns were successfully produced. Due definition of the photolithography, no limitations geometry exist. Any can be created enable fine control fluid motion...

A unique flow field pattern in a bio-functional microchannel is utilized to significantly enhance the performance of microsystem developed for selectively isolating circulating tumor cells from cell suspensions. For high such systems, disposal maximum non-target species just as important retention target species; unfortunately, most studies ignore or fail report this aspect. Therefore, sensitivity and specificity are introduced quantitative criteria evaluate system enabling direct comparison...

In comparison with conventional heat treatment, high-temperature rapid thermal annealing (RTA) in a radio frequency (RF) induction-heated system can reduce or eliminate residual stresses thin films few seconds. this work, changes the stress level due to RTA of polycrystalline silicon were studied as function time and temperature. The corresponding variations microstructure surface layer experimentally investigated by variety analytical tools. results suggest that evolution during is...

An integrated microchannel heat sink consisting of shallow, nearly rectangular microchannels has been fabricated using standard micromachining techniques to highlight the effects micrometer sized channel shape on evolving flow patterns and, consequently, thermal performance microsystem. heater serves as a local source, while an array micro thermistors is used for temperature distribution measurements. The working fluid, DI water, pressurized through forced convection transfer studies....

A new technology approach for the design, fabrication and application of an integrated free-solution capillary electrophoresis microsystem is presented. Combining advantages projection, contact photolithography deep-reactive-ion-etching, this allows fast flexible formation micron-sized channels with extremely high aspect-ratio (>50:1) sub-micron pillar arrays on a silicon substrate. Utilizing fluorescence video microscopy, DNA separation has been demonstrated. Furthermore, detailed...

Forced convection boiling in microchannels is studied experimentally under the uniform heat flux boundary condition.Several microchannel sinks with integrated temperature sensors, spanning two orders of magnitude height 5-500 µm, have been fabricated designed nucleation sites on bottom surfaces.The are capped by a glass wafer to monitor bubble activity using video microscopy.Distributed micro heater elements device backside used as source, while working liquid flow rate adjusted syringe...

Dynamic states of cancer cells moving under shear flow in an antibody-functionalized microchannel are investigated experimentally and theoretically. The cell motion is analyzed with the aid a simplified physical model featuring receptor-coated rigid sphere above solid surface immobilized ligands. described by Langevin equation accounting for hydrodynamic loadings, gravitational force, receptor-ligand bindings, thermal fluctuations; bonds modeled as linear springs. Depending on applied rate,...

A freestanding microchannel, with integrated temperature sensors, has been developed for high-pressure flow studies. These microchannels are approximately 20 /spl mu/m/spl times/2 times/4400 mu/m, and suspended above 80 mu/m deep cavities, bulk micromachined using BrF/sub 3/ dry etch. The calibration of the lightly boron-doped thermistor-type sensors shows that resistance sensitivity these is parabolic respect to linear pressure. Volumetric rates NZ in microchannel were measured at inlet...

A video system has been designed to monitor in situ and accurately the etching of sacrificial phosphosilicate-glass (PSG) microchannels using hydrofluoric acid (HF). An universal model, which predicts length vs. time over a wide range HF concentration (3-49 wt.%), identified. In addition diffusion, this model is based on first-and-second order chemical reaction mechanism. It found that PSG microchannel rate sensitive channel thickness but not width. Finally, bubble formation movement inside...

Constriction devices contain elements inserted into the fluid stream, which change local streamwise flow area. One such element is orifice-like obstruction with sharp corners, a back-to-back abrupt contraction and expansion, could trigger separation. A series of microchannels, 40 /spl mu/m times/ 1 4000 in nominal dimensions, constriction at centers channels has been fabricated using standard micromachining techniques. The channel widths sections varied from 10 to 34 mu/m, pressure sensors...

Microfabricated electric generators, scavenging ambient mechanical energy, are potential power sources for autonomous systems. Described presently the design, modeling, and implementation of a single-wafer floating-electrode microgenerator, integrating micromechanical resonator number electronic devices. Forming plate variable capacitor, is responsible converting vibration to electricity. A sense transistor diode bridge integrated, respectively, monitoring "charging" floating electrode...

The adhesion dynamics of circulating tumor cells in a bio-functionalized microchannel under hydrodynamic loading is explored experimentally and analyzed theoretically. EpCAM antibodies are immobilized on the surface to specifically capture EpCAM-expressing target breast cancer MDA-MB-231 from homogeneous cell suspension shear flow. In cross-stream direction, gravity dominant physical mechanism resulting continuous interaction between receptors anti-EpCAM ligands. Depending applied rate,...

Fluid flow in microdevices consisting of pairs microchannels series was studied. The dimensions the channels are about 40 μm × 1 2000 for wide and 20 narrow channels. Pairs channels, with integrated pressure sensors, connected via transition sections included angles varying from 5° to 180°. Minor losses (not due friction) were studied by passing nitrogen through under inlet pressures up 60 p.s.i. Each device tested contraction mode, channel, opposite expansion channel. Mass rate first...