Sub-micrometer bioparticles are separated by size in a microfluidic channel utilizing a ratchet migration mechanism. A structure within the microfluidic channel includes an array of micro-posts arranged in laterally shifted rows. Reservoirs are disposed at each end of the microfluidic channel. A biased AC potential is applied across the channel via electrodes immersed into fluid in each of the reservoirs to induce a non-uniform electric field through the microfluidic channel. The applied potential comprises a first waveform with a first frequency that induces electro-kinetic flow of sub-micrometer bioparticles in the microfluidic channel, and an intermittent superimposed second waveform with a higher frequency. The second waveform selectively induces a dielectrophoretic trapping force to selectively impart ratchet migration based on particle size for separating the sub-micrometer bioparticles by size in the microfluidic channel.

Microfluidic devices having a circuit substrate with a control unit, a switching mechanism associated with a dielectrophoresis (DEP) electrode, and a memory unit are described. Switching instructions may be received, stored, and retrieved by the control unit and used to control the DEP electrode via the switching mechanism. Systems comprising the described microfluidic devices and methods of controlling the described microfluidic devices are included herein.

A novel Self-Locking Optoelectronic Tweezers (SLOT) for single microparticle manipulation across a large area is provided. DEP forces generated from ring-shape lateral phototransistors are utilized for locking single microparticles or cells in the dark state. The locked microparticles or cells can be selectively released by optically deactivating these locking sites.

The invention relates to a method for operating a fluidic microsystem (100) for the dielectrophoretic manipulation of suspended particles (1) having a particle diameter in a suspension liquid (2), wherein the microsystem (100) comprises: —a channel (10) having a longitudinal direction; —an electrode device (20) having an electrode (21), the longitudinal extent of which deviates from the longitudinal direction of the channel (10) and which has individually controllable electrode segments (22) for producing dielectrophoretic forces which act on the particles (1), each electrode segment (22) having a deflection angle α, relative to the longitudinal direction of the channel (10), and a segment length (s.sub.i), which determine a segment offset (D.sub.i) perpendicular to the longitudinal direction of the channel (10); and—a control device (30). The method comprises: —producing a flow of the suspension liquid (2) with a flow velocity so that the particles (1) successively pass through an interaction region of the electrode (21), which interaction region is spanned by the electrode segments (22); and—activating the electrode segments (22) in order to deflect the particles (1) onto predetermined motion paths (4, 5), which are determined by a superposition of flow forces in the flow of the suspension liquid (2) and of the dielectrophoretic forces at the electrode segments (22). During the passage of each particle, each of the electrode segments (22) which are passed by the particle (1) is activated in a clocked manner for a predetermined activation duration, according to the desired motion path (4, 5), the activation duration of each electrode segment (22) being determined by the quotient of the segment length (s.sub.i) of the electrode segment (22) and the flow velocity. The electrode segments (22) are dimensioned such that the segment offset (D.sub.i) of each electrode segment (22) is less than the particle diameter. For the deflection of each particle (1), at least two successive electrode segments (22) cooperate.

A detection method is a detection method for detecting a target substance from among in-liquid substances including the target substance and a non-target substance, and includes (i) applying an alternating-current voltage to an electrode pair that generates an electric field gradient so that positive dielectrophoretic force is exerted on the target substance and the non-target substance; and (ii) applying an alternating-current voltage after execution of the (i) applying so that negative dielectrophoretic force is exerted on the target substance on which the positive dielectrophoretic force has been acting.

Systems, methods, and devices are described herein for identifying, monitoring, isolating, or selecting a cell having a predefined characteristic in a mixed population of cells utilizing a combination of any one or more of iDEP, a region of localized field enhancement, a variable frequency electric field, a wide bandwidth amplifier, and/or an imaging apparatus.

Biological activity in holding pens in a micro-fluidic device can be assayed by placing in the holding pens capture objects that bind a particular material of interest produced by the biological activity. The biological material of interest that binds to each capture object can then be assessed, either in the micro-fluidic device or after exporting the capture object from the micro-fluidic device. The assessment can be utilized to characterize the biological activity in each holding pen. The biological activity can be production of the biological material of interest. Thus, the biological activity can correspond to or arise from one or more biological cells. Biological cells within a holding pen can be clonal cell colonies. The biological activity of each clonal cell colony can be assayed while maintaining the clonal status of each colony.

Methods and apparatus providing for the isolation of an unknown mutation from a sample comprising wild type nucleic acids and mutated nucleic acids through the application of time-varying driving fields and periodically varying mobility-altering fields to the sample within in an affinity matrix.

The present technology relates to improved device and methods of use of insulator-based dielectrophoresis. This device provides a multi-length scale element that provides enhanced resolution and separation. The device provides improved particle streamlines, trapping efficiency, and induces laterally similar environments. Also provided are methods of using the device.

The present invention includes methods, devices and systems for isolating, identifying, analyzing, and quantifying biological materials from fluid samples. In various aspects, the methods, devices and systems may allow for a rapid procedure that requires a minimal amount of material and/or results in high purity biological materials from complex fluids such as blood, serum, or plasma.