Abstract: The present disclosure provides a method for performing agglutination assays on a “two plate” DMF device format. Droplets containing analytes of interest (particles, cells, etc.) are loaded into the DMF device and mixed with solution-phase or dried agglutinating antibodies or antigens. The agglutinating agents bind to their complementary targets (e.g. antibodies or antigens for example) in the sample droplets, which leads to the formation of insoluble aggregates. Active mixing on a DMF device reduces the reaction time and enhances the agglutination effect. Since the agglutinated sample is sandwiched between two plates on the DMF device, it is straightforward to visualize the result by eye or via a digital camera.

Abstract: Methods are provided for the preparation of a sample using a digital microfluidic platform and the optional subsequent mass analysis of an extracted analyte. A sample is dried, optionally on a solid phase support, and contacted with digital microfluidic array. An analyte present within the dried sample is extracted into an extraction solvent by electrically addressing the digital microfluidic array to transport a droplet of extraction solvent to the dried sample spot. The extracted sample may be dried and subsequently processed on the digital micro fluidic array for derivatization. The digital microfluidic device may further include an integrated microfluidic channel having an output aperture, and the method may further include contacting a droplet containing extracted analyte with the microfluidic channel and applying a suitable electric field for generating nano-electrospray, thereby enabling the device to be directly interacted with a mass analysis device.

Abstract: The present disclosure discloses a multi-droplet sensing and actuation system, for use in a digital microfluidic chip operation wherein a linearly independent alternating current signal is applied to each discrete actuation electrode thus encoding the electrode's identity. The combined measured impedance signal from multiple channels is then processed to decode an impedance measurement for the volume between each discrete actuation electrode and its corresponding conductive counter electrode region, where the sensed impedance is inversely proportional to an amount of liquid within the volume.

Abstract: Methods are provided for the preparation of a sample using a digital microfluidic platform and the optional subsequent mass analysis of an extracted analyze. A sample is dried, optionally on a solid phase support, and contacted with digital microfluidic array. An analyte present within the dried sample is extracted into an extraction solvent by electrically addressing the digital microfluidic array to transport a droplet of extraction solvent to the dried sample spot. The extracted sample may be dried and subsequently processed on the digital micro fluidic array for derivatization. The digital microfluidic device may further include an integrated microfluidic channel having an output aperture, and the method may further include contacting a droplet containing extracted analyte with the microfluidic channel and applying a suitable electric field for generating nano-electrospray, thereby enabling the device to be directly interacted with a mass analysis device.

Abstract: The present disclosure discloses a multi-droplet sensing and actuation system, for use in a digital microfluidic chip operation wherein a linearly independent alternating current signal is applied to each discrete actuation electrode thus encoding the electrode's identity. The combined measured impedance signal from multiple channels is then processed to decode an impedance measurement for the volume between each discrete actuation electrode and its corresponding conductive counter electrode region, where the sensed impedance is inversely proportional to an amount of liquid within the volume.

Abstract: Methods are provided for the preparation of a sample using a digital microfluidic platform and the optional subsequent mass analysis of an extracted analyte. A sample is dried, optionally on a solid phase support, and contacted with digital microfluidic array. An analyte present within the dried sample is extracted into an extraction solvent by electrically addressing the digital microfluidic array to transport a droplet of extraction solvent to the dried sample spot. The extracted sample may be dried and subsequently processed on the digital microfluidic array for derivatization. The digital microfluidic device may further include an integrated microfluidic channel having an output aperture, and the method may further include contacting a droplet containing extracted analyte with the microfluidic channel and applying a suitable electric field for generating nano-electrospray, thereby enabling the device to be directly interfaced with a mass analysis device.

Abstract: Methods and devices for liquid-liquid extraction using digital microfluidic arrays are provided. A polar droplet is transported to a separation region containing a substantially non-polar solvent, where non-polar impurities may be extracted from the polar droplet while maintaining a distinct phase separation. In a preferred embodiment, biological samples containing hormones are dried on a digital microfluidic array, lysed by a lysing solvent, dried, subsequently dissolved in a polar solvent, and further purified in a separation step in which droplets are transported through a volume of non-polar solvent. The method disclosed herein provides the distinct advantage of an automated sample preparation method that is capable of extracting hormones from low sample volumes with high precision and recovery.

Abstract: Methods and devices for liquid-liquid extraction using digital microfluidic arrays are provided. A polar droplet is transported to a separation region containing a substantially non-polar solvent, where non-polar impurities may be extracted from the polar droplet while maintaining a distinct phase separation. In a preferred embodiment, biological samples containing hormones are dried on a digital microfluidic array, lysed by a lysing solvent, dried, subsequently dissolved in a polar solvent, and further purified in a separation step in which droplets are transported through a volume of non-polar solvent. The method disclosed herein provides the distinct advantage of an automated sample preparation method that is capable of extracting hormones from low sample volumes with high precision and recovery.

Abstract: Devices and systems are provided in which one or more electrochemical sensors are integrated within a digital microfluidic device. According to one example embodiment, a two-electrode electrochemical sensor is integrated into a top or bottom plate of a digital microfluidic device, where the counter electrode is provided within a defined spatial region, and where the working electrode is formed such that it is spatially distributed within the spatial region associated with the counter electrode. The working electrode may be provided as one or more elongate segments that are spatially distributed within, and/or surround a perimeter of, the counter electrode. The area of the working electrode may be selected to be smaller than that of the counter electrode in order to improve the performance of the electrochemical sensor.

Abstract: Embodiments of the present disclosure digital microfluidic arrays that may be fabricated by a printing method, whereby digital microfluidic electrodes arrays are printed, via a printing method such as inkjet printing, onto a suitable substrate. In some embodiments, a substrate and/or ink is prepared or modified to support the printing of electrode arrays, such as via changes to the surface energy. In some embodiments, porous and/or fibrous substrates are prepared by the addition of a barrier layer, or, for example, by the addition or infiltration of a suitable material to render the surface capable of supporting printed electrodes. Various example embodiments involving hybrid devices formed by the printing of digital microfluidic arrays onto a substrate having a hydrophilic layer are disclosed.

Abstract: Devices and methods are provided for performing droplet-based solid phase processing steps on a digital microfluidic device. A solid phase material, which may be a porous solid phase material such as a porous polymer monolith is formed or located on a digital microfluidic element. The solid phase may be formed by an in-situ method in which the digital microfluidic array is actuated to transport a droplet of solid phase pre-cursor solution to a selected element on the array, and subsequently processed to form a solid phase on the array element. The integration of a solid phase material with a digital microfluidic array enables a wide range of applications including solid phase extraction and sample concentration.

Abstract: Devices and methods for implementing cell-based assays and long-term cell culture. The device and method are based on digital microfluidics (DMF) which is used to actuate nanoliter droplets of reagents and cells on a planar array of electrodes. DMF method is suitable for assaying and culturing both cells in suspension and cells grown on surface (adherent cells). This method is advantageous for cell culture and assays due to the automated manipulation of multiple reagents in addition to reduced reagent use and analysis time. No adverse effects of actuation by DMF were observed in assays for cell viability, proliferation, and biochemistry. These results suggest that DMF has great potential as a simple yet versatile analytical tool for implementing cell-based assays and cell culture on the microscale.

Abstract: Digital microfluidic devices, and methods for the control and fabrication thereof, and provided in which an integrated nanostructured electrodeposited electrode is provided such that the digital microfluidic array can be actuated to contact a droplet with the nanostructured electrodeposited electrode. In some embodiments, digital microfluidic devices are provided having an integrated electrochemical sensor, where the working electrode is provided in the form of a nanostructured electrodeposited electrode. Various methods of fabricating such integrated device are described, including methods that employ a lift-off process that exposes an underlying base electrode for the electrodeposition of a nanostructured electrodeposited electrode, while providing a hydrophobic surface for droplet transport.

Abstract: The present invention provides a hybrid digital and channel microfluidic device in the form of an integrated structure in which a droplet may be transported by a digital microfluidic array and transferred to a microfluidic channel. In one aspect of the invention, a hybrid device comprises a first substrate having a digital microfluidic array capable of transporting a droplet to a transfer location, and a second substrate having a microfluidic channel. The first and second substrates are affixed to form a hybrid device in which an opening in the microfluidic channel is positioned adjacent to the transfer location, so that a droplet transported to the transfer location contacts the channel opening and may enter the channel. The invention also provides methods of performing separations using a hybrid digital and channel microfluidic device and methods of assembling a hybrid digital microfluidic device.

Abstract: The present invention provides exchangeable, reagent pre-loaded carriers (10), preferably in the form of plastic sheets, which can be temporarily applied to an electrode array (16) on a digital microfluidic (DMF) device (14). The carrier (10) facilitates virtually un-limited re-use of the DMF devices (14) avoiding cross-contamination on the electrode array (16) itself, as well as enabling rapid exchange of pre-loaded reagents (12) while bridging the world-to-chip interface of DMF devices (14). The present invention allows for the transformation of DMF into a versatile platform for lab-on-a-chip applications.

Abstract: We introduce a new method for implementing cell-based assays and long-term cell culture. The method is based on digital microfluidics (DMF) which is used to actuate nanoliter droplets of reagents and cells on a planar array of electrodes. DMF method is suitable for assaying and culturing both cells in suspension and cells grown on surface (adherent cells). This method is advantageous for cell culture and assays due to the automated manipulation of multiple reagents in addition to reduced reagent use and analysis time. No adverse effects of actuation by DMF were observed in assays for cell viability, proliferation, and biochemistry. These results suggest that DMF has great potential as a simple yet versatile analytical tool for implementing cell-based assays and cell culture on the microscale.

Abstract: Devices and methods are provided for performing droplet-based solid phase processing steps on a digital microfluidic device. A solid phase material, which may be a porous solid phase material such as a porous polymer monolith is formed or located on a digital microfluidic element. The solid phase may be formed by an in-situ method in which the digital microfluidic array is actuated to transport a droplet of solid phase pre-cursor solution to a selected element on the array, and subsequently processed to form a solid phase on the array element. The integration of a solid phase material with a digital microfluidic array enables a wide range of applications including solid phase extraction and sample concentration.

Abstract: Methods are provided for the preparation of a sample using a digital microfluidic platform and the optional subsequent mass analysis of an extracted analyte. A sample is dried, optionally on a solid phase support, and contacted with digital microfluidic array. An analyte present within the dried sample is extracted into an extraction solvent by electrically addressing the digital microfluidic array to transport a droplet of extraction solvent to the dried sample spot. The extracted sample may be dried and subsequently processed on the digital microfluidic array for derivatization. The digital microfluidic device may further include an integrated microfluidic channel having an output aperture, and the method may further include contacting a droplet containing extracted analyte with the microfluidic channel and applying a suitable electric field for generating nano-electrospray, thereby enabling the device to be directly interfaced with a mass analysis device.

Abstract: We introduce a method for implementing cell-based assays and long-term cell culture. The method is based on digital microfluidics (DMF) which is used to actuate nanoliter droplets of reagents and cells on a planar array of electrodes. DMF method is sutable for assaying and culturing both cells in suspension and cells grown on surface (adherent cells). This method is advantageous for cell culture and assays due to the automated manipulation of multiple reagents in addition to reduced reagent use and analysis time. No adverse effects of actuation by DMF were observed in assays for cell viability, proliferation, and biochemistry. These results suggest that DMF has great potential as a simple yet versatile analytical tool for implementing cell-based assays and cell culture on the microscale.

Abstract: A method of extracting hormones from a biological sample using digital microfluidic arrays is provided. Biological samples containing hormones are dried on a digital microfluidic array, lysed by a lysing solvent, dried, subsequently dissolved in a polar solvent, and further purified in an extraction step in which droplets are transported through a volume of non-polar solvent. The method disclosed herein provides the distinct advantage of an automated sample preparation method that is capable of extracting hormones from low sample volumes with excellent precision and recovery.