Microfluidic devices containing reversibly pinned droplet samples and methods
Inventors
Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
Assignees
Member
NucleraNuclera develops automated benchtop platforms and integrated systems for rapid protein expression, optimization, and purification, utilizing cell-free synthesis, digital microfluidics, and software-driven workflows. Their technology enables miniaturized and scalable protein prototyping—including challenging targets such as membrane proteins—directly at the lab bench. Nuclera serves academic and industrial researchers, focusing on reducing turnaround time for functional protein access and streamlining screening and production. The company has secured significant funding to enable broad commercialization, expanded their leadership team to support scale-up, and continues to drive advancements in drug discovery, proteomics, and experimental automation.
Nuclera develops automated benchtop platforms and integrated systems for rapid protein expression, optimization, and purification, utilizing cell-free synthesis, digital microfluidics, and software-driven workflows. Their technology enables miniaturized and scalable protein prototyping—including challenging targets such as membrane proteins—directly at the lab bench. Nuclera serves academic and industrial researchers, focusing on reducing turnaround time for functional protein access and streamlining screening and production. The company has secured significant funding to enable broad commercialization, expanded their leadership team to support scale-up, and continues to drive advancements in drug discovery, proteomics, and experimental automation.
Publication Number
US-11554375-B2
Publication Date
2023-01-17
Expiration Date
Abstract
A microfluidic device comprising: (a) a plate comprising a substrate, a plurality of electrodes, and a first layer of hydrophobic material applied over the plurality of electrodes; (b) a processing unit operably programmed to perform a method of pinning an aqueous droplet within the microfluidic device; and (c) a controller operably connected to a power source, the processing unit, and the plurality of electrodes. The method of pinning an aqueous droplet comprises: applying an electric field of a first polarity to an aqueous droplet located on the surface of the layer of hydrophobic material and having a first contact angle, to cause the droplet to maintain a second contact angle in the absence of the electric field, wherein the aqueous droplet contains a surfactant and the second contact angle is less than the first contact angle.
Core Innovation
A microfluidic device comprising a plate with a substrate, a plurality of electrodes, and a first layer of hydrophobic material applied over the plurality of electrodes, a processing unit operably programmed to perform a method of pinning an aqueous droplet, and a controller operably connected to a power source, the processing unit, and the plurality of electrodes. The method of pinning an aqueous droplet comprises applying an electric field of a first polarity to an aqueous droplet located on the surface of the layer of hydrophobic material and having a first contact angle, to cause the droplet to maintain a second contact angle in the absence of the electric field, wherein the aqueous droplet contains a surfactant and the second contact angle is less than the first contact angle.
A dual-plate embodiment comprises a top plate having a top substrate, a first layer of hydrophobic material, and a top continuous conductor between the first layer of hydrophobic material and the top substrate, and a bottom plate comprising a bottom substrate, a plurality of electrodes and a second layer of hydrophobic material applied over the plurality of electrodes, with a gap between the first and second layers of hydrophobic material. The method of pinning in the dual-plate embodiment comprises applying an electric field of a first polarity to an aqueous droplet located in the gap, causing the droplet's maximum diameter to increase and to maintain the increased maximum diameter in the absence of the electric field, wherein the aqueous droplet contains a surfactant.
The background identifies that conventional EWoD devices often require a continuous low voltage holding force to maintain droplet position, which requires constant actuation and may degrade the EWoD device or the biological sample and is energy inefficient. Accordingly, there is a need for an improved EWoD device capable of temporarily pinning a droplet in a desired location on the array that does not require a constant application of voltage.
Claims Coverage
The independent claims define two inventive features corresponding to two methods of pinning aqueous droplets: one for a single-plate configuration and one for a dual-plate (gap) configuration.
Pinning an aqueous droplet on a hydrophobic-coated electrode plate
A method in a microfluidic device comprising a plate with a plurality of electrodes and a layer of hydrophobic material completely covering the plurality of electrodes; introducing an aqueous droplet containing a surfactant to the hydrophobic surface having a first contact angle (first contact angle ≥ 90°); and applying an electric field of a first polarity at a first place for a first time thereby causing the aqueous droplet to maintain a second contact angle in the absence of the electric field after the first time (the second contact angle is less than the first contact angle and is < 90°), whereby the aqueous droplet remains in the first place and does not drift.
Pinning an aqueous droplet in a gap between hydrophobic layers by increasing and maintaining droplet diameter
A method in a microfluidic device comprising a top plate with a first hydrophobic layer and a continuous conductor between the first hydrophobic layer and the top substrate, and a bottom plate with a plurality of electrodes and a second hydrophobic layer completely covering the plurality of electrodes, defining a gap; introducing an aqueous droplet containing a surfactant into the gap with a measurable diameter; and applying an electric field of a first polarity at a first place during a first time, thereby causing the diameter to increase to an increased diameter and to maintain the increased diameter in the absence of the electric field after the first time, whereby the aqueous droplet remains in the first place on the second hydrophobic layer and does not drift.
The independent claims describe two core inventive methods for reversible droplet pinning: reducing and maintaining a droplet contact angle on a single hydrophobic-coated electrode plate, and increasing and maintaining droplet maximum diameter in a gap between hydrophobic layers, both requiring the droplet to contain a surfactant so the droplet remains in place without continuous voltage.
Stated Advantages
Aqueous droplets resist drift in the absence of an electric field.
Devices requiring less power for operation.
Increased operational lifetime of the devices.
Less likely to adversely affect biological materials within the droplet samples.
Documented Applications
Sample preparation, assays, and synthetic chemistry performed with tiny quantities of samples and reagents (lab-on-a-chip).
Massively parallel assays and reactions enabled by active matrix EWoD arrays with many addressable electrodes.
General droplet operations including loading, dispensing, splitting, separating, transporting, merging, diluting, mixing, agitating, deforming, retaining, incubating, heating, vaporizing, cooling, disposing of, and transporting droplets out of a microfluidic device.
Analytical procedures using light-transmissive substrates, including fluorescence measurements, absorption measurements in IR/UV/visible wavelengths, and attenuated total-internal reflection spectroscopy.
Biochemical protocols and assays including nucleic acid amplification protocols, affinity-based assay protocols, enzymatic assay protocols, gene sequencing and protein sequencing protocols, and analyses of biological fluids.
Synthesis of oligonucleotides and other biochemical synthetic methods described as examples of droplet contents and uses.
Interested in licensing this patent?