Abstract: A method is provided of obtaining a sample concentration of a solution in a microfluidic device. The microfluidic device includes a channel having a reservoir and a collection port. The channel is filled with a solution having particles therein. A reservoir drop is deposited over the reservoir of the channel such that the solution of the channel flows towards the collection port in response to evaporation of the solution at the collection port. The particles at the collection port are collected to obtain the sample concentration.

Abstract: A method is provided for fabricating a microstructure using maskless lithography. A first layer is provided in a spaced relationship to a base layer so as to define a construction cavity therebetween. The first layer has a passageway therethrough that communicates with the construction cavity. The construction cavity is filled with material and a polymerizing agent is directed towards a portion of the material so as to polymerize the same. The polymerized material defines a channel network and the non-polymerized material is flushed from the channel network.

Abstract: A method is provided for fabricating a constriction region in a channel of a microfluidic device. The method includes the steps of introducing a pre-polymer mixture including a monomer, cross-linking agent and photoinitiator into the channel. The pre-polymer mixture is polymerized at a localized area of the channel so as to shrink and solidify the liquid mixture. The solidified and shrunken liquid mixture provides the constriction region in the channel.

Abstract: A method is provided for performing a gradient-based assay in a microfluidic device. The method includes the steps of passing first and second fluids through a channel in the microfluidic device. The first fluid has a predetermined concentration of particles therein such that the particles in the first fluid diffuse into the second fluid so as to cause a gradient of concentration of particles in the second fluid as the second fluid flows through the channel. The second fluid sequentially intersects a series of targets along the channel wall as the second fluid flows through the channel.

Abstract: A microfluidic device is provided for regulating the temperature of a sample fluid flowing therethrough, as well as, a method of regulating the temperature of the sample fluid flowing through the microfluidic device. The microfluidic device includes a body member defining a fluid channel for allowing the sample fluid to flow therethrough and a first regulating channel. A regulating fluid having a predetermined temperature flows through the regulating channel adjacent the fluid channel so as to effectuate a heat exchange with the sample fluid flowing through the fluid channel to regulate the temperature thereof.

Abstract: An integrated biological microfluidic system and method of using the same is provided. The microfluidic system includes a microfluidic device having a channel therethrough. A filter and a vesicle containing a predetermined cargo are positioned in the channel. The vesicle has outer surface carrying a bioactive molecule. A reagent having predetermined stimuli therein flows through the channel and carries the vesicle to the filter. If the bioactive molecule is activated by the predetermined stimuli, lysis of the vesicle is triggered, thereby releasing the cargo. The cargo flows through the filter and engages a visual detection structure positioned in the channel downstream of the filter. The visual detection structure provides a visual display in response to exposure to the cargo.

Abstract: The present invention provides a novel microscale fluid handling system for initiating, culturing, manipulating and assaying three-dimensional multicellular assembly. The system including a microfluidic device and three-dimensional multicellular tissue surrogate assembly. The device of the invention includes at least one microfluidic channel; and at least one chamber, wherein the walls of the chamber are lined with a cell layer; and wherein fluid medium flows through each of the channels and chambers. Also, disclosed are methods for using the device to introducing test agents to the multicellular assemblies to observe biological responses thereof.

Abstract: A method of fabricating a microstructure is provided. The method includes the step of providing a layer of a polyermizable material. A solid is brought into contact with the layer of polymerizable material so as to alter the shape of the upper surface of the layer. Thereafter, the layer of polymerizable material is polymerized such that the layer solidifies and the upper surface thereof assumes a desired three-dimensional configuration.

Abstract: A flow of liquids is carried out on a microscale utilizing surface effects to guide the liquid on flow paths to maintain laminar flow. No sidewall confining structure is required, minimizing resistance to flow and allowing laminar flow to be maintained at high flow rates. The guiding structure has flow guiding stripes formed on one or both of facing base and cover surfaces which are wettable by a selected liquid to direct the liquid from a source location to a destination location. The regions adjacent to the guiding stripes on the base and cover surfaces are non-wettable. The smooth interface between the gas and liquid along the flowing stream allows gas-liquid reactions to take place as a function of diffusion across the interface without mixing of the gas and liquid. Liquid-liquid flows may also be guided with such structures.

Abstract: A method is provided for fabricating a multi-layer microfluidic device on a base. A first layer is positioned on the base in a spaced relationship thereto so as to define a construction cavity therebetween. The first layer has a passageway therethrough which communicates with the construction cavity. A mask is positioned between the construction cavity and an ultraviolet source. The mask corresponds to a channel to be formed in the construction cavity. The construction cavity is filled with material and a portion of the material is polymerized within the construction cavity so as to solidify the same. The solidified material defines the channel. Thereafter, the material is flushed from the channel in the construction cavity.

Abstract: A method is provided for fabricating a three-dimensional device. The method includes the steps of providing a container defining a chamber and filling the chamber with a polymerizable material. Masks are positioned between a polymerizing agent and corresponding portions of polymerizable material. The polymerizing agent passes through the masks so as to polymerize selected portions of the polymerizable material within a chamber of the container and form the three-dimensional device.

Abstract: A method is provided for performing a gradient-based assay in a microfluidic device. The method includes the steps of passing first and second fluids through a channel in the microfluidic device. The first fluid has a predetermined concentration of particles therein such that the particles in the first fluid diffuse into the second fluid so as to cause a gradient of concentration of particles in the second fluid as the second fluid flows through the channel. The second fluid sequentially intersects a series of targets along the channel wall as the second fluid flows through the channel.

Abstract: A method is provided for fabricating a microstructure using maskless lithography. A first layer is provided in a spaced relationship to a base layer so as to define a construction cavity therebetween. The first layer has a passageway therethrough that communicates with the construction cavity. The construction cavity is filled with material and a polymerizing agent is directed towards a portion of the material so as to polymerize the same. The polymerized material defines a channel network and the non-polymerized material is flushed from the channel network.

Abstract: Microfluidic embryo scaled channels for handling and positioning embryos provide the opportunity to evaluate and treat embryos in improved manners Fluid flow is used to move and position embryos within microfluidic channels and channel geometries may be used to place embryos at specific locations. Surface properties and compliance (deformation) properties of embryos are evaluated as a predictor of viability. The microfluidic channels provide the opportunity for fine controls of pressure to conduct various evaluations at forces slightly below which damage to embryos is known to occur.

Abstract: A method is provided of obtaining a sample concentration of a solution in a microfluidic device. The microfluidic device includes a channel having a reservoir and a collection port. The channel is filled with a solution having particles therein. A reservoir drop is deposited over the reservoir of the channel such that the solution of the channel flows towards the collection port in response to evaporation of the solution at the collection port. The particles at the collection port are collected to obtain the sample concentration.

Abstract: A microfluidic device is provided for regulating the temperature of a sample fluid flowing therethrough, as well as, a method of regulating the temperature of the sample fluid flowing through the microfluidic device. The microfluidic device includes a body member defining a fluid channel for allowing the sample fluid to flow therethrough and a first regulating channel. A regulating fluid having a predetermined temperature flows through the regulating channel adjacent the fluid channel so as to effectuate a heat exchange with the sample fluid flowing through the fluid channel to regulate the temperature thereof.

Abstract: A method is provided for fabricating a constriction region in a channel of a microfluidic device. The method includes the steps of introducing a pre-polymer mixture including a monomer, cross-linking agent and photoinitiator into the channel. The pre-polymer mixture is polymerized at a localized area of the channel so as to shrink and solidify the liquid mixture. The solidified and shrunken liquid mixture provides the constriction region in the channel.

Abstract: A method is provided for pumping fluid through a channel of a microfluidic device. The channel has an input port of a predetermined radius and an output port of a predetermined radius. The channel is filled with fluid and a pressure gradient is generated between the fluid between the input port and the fluid at the output port. As a result, fluid flows through the channel towards the output port.

Abstract: A method and apparatus is provided for monitoring the environment within a microfluidic device. The microfluidic device includes a body defining a channel for accommodating flow of fluid therethrough. A monitor structure is disposed in the channel of the body in the flow of fluid. The monitor structure changes color and/or dimension in response to various parameters of the fluid having predetermined values.

Abstract: A method is provided for fabricating a multi-layer microfluidic device on a base. A first layer is positioned on the base in a spaced relationship thereto so as to define a construction cavity therebetween. The first layer has a passageway therethrough which communicates with the construction cavity. A mask is positioned between the construction cavity and an ultraviolet source. The mask corresponds to a channel to be formed in the construction cavity. The construction cavity is filled with material and a portion of the material is polymerized within the construction cavity so as to solidify the same. The solidified material defines the channel. Thereafter, the material is flushed from the channel in the construction cavity.