Graphene-based dielectrophoresis sensor and method
Inventors
Koester, Steven John • Oh, Sang-Hyun
Assignees
University of Minnesota System
Publication Number
US-12325031-B2
Publication Date
2025-06-10
Expiration Date
2039-06-05
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Abstract
A dielectrophoretic (DEP) sensor includes a graphene electrode adjacent a channel for confining a target particle in a liquid, a surface probe attached to a surface of the graphene electrode, the surface probe having a selective reaction with the target particle, and a voltage source electrically connected to the graphene electrode and configured to apply a voltage to the graphene electrode to cause DEP trapping of the target particle at the graphene electrode.
Core Innovation
The invention describes a dielectrophoretic (DEP) sensor that utilizes a graphene electrode adjacent to a channel for confining a target particle in a liquid. A surface probe is attached to the graphene electrode, and this probe is designed to have a selective reaction with a specific target particle. A voltage source is used to apply a voltage to the graphene electrode, which causes DEP trapping of the target particle at or near the surface of the electrode. The sensor can operate in either resistive or capacitive sensing modes to detect the presence of the target particle.
The problem addressed by this invention is the limitation of existing pathogen detection methods, which often rely on time-consuming and costly techniques such as culture and polymerase chain reaction (PCR) analysis. These methods are not rapid or sensitive enough for hand-held or point-of-care systems, and conventional graphene sensors depend on slow diffusion-based processes to attract analytes. While DEP can attract particles quickly, it does not inherently provide selectivity. The invention aims to combine the high sensitivity of graphene sensors, the particle-attracting power of DEP, and specific selective detection through surface functionalization.
By surface functionalizing the graphene electrode with a probe that can bind selectively to the target particle, the sensor achieves both specificity and rapid sensing. The DEP technique accelerates the attraction of target particles to the sensor surface, and the selectivity is imparted by the functionalization of the graphene with probes (such as DNA, proteins, or other molecules) that selectively react with the desired target. The sensor's readout is designed to be independent of the DEP excitation, allowing reliable detection even in the presence of high electric fields used for particle trapping.
Claims Coverage
The patent includes one independent claim outlining several inventive features of the graphene-based dielectrophoretic sensor.
Graphene electrode with adjacent channel and surface probe for selective DEP sensing
The sensor comprises a graphene electrode positioned next to a channel that confines a target particle in a liquid. A surface probe is attached to the graphene electrode, and this probe has a selective reaction with the target particle. The graphene electrode extends between a first and a second electrical contact.
Second electrode overlapping graphene electrode for DEP trapping
A second electrode overlaps the graphene electrode and connects to the second electrical contact. A voltage source is configured to vary the voltage between the graphene electrode and the second electrode, enabling dielectrophoretic (DEP) trapping of the target particle at the graphene electrode.
Readout system for presence detection based on current
A source meter is electrically connected to the first and second electrical contacts. It applies a measurement signal to the graphene electrode, sufficient to read out a response from the sensor that indicates the presence of the target particle by measuring the current through the graphene electrode.
The inventive features define an integrated system combining a graphene electrode functionalized for selectivity, an overlapping second electrode for DEP trapping, and a measurement system for detecting trapped target particles based on electrical readout.
Stated Advantages
The invention achieves selectivity to a range of target molecules or biological particles using a DEP-based graphene sensor.
Embodiments enable readout of the sensor response independent of the relatively large AC excitation used for DEP particle attraction.
The sensor provides rapid detection compared to diffusion-based sensing methods by using DEP to attract target particles quickly to the graphene surface.
Documented Applications
The sensors and techniques can be used in point of care sensors.
Embodiments are deployable in DNA-based bar-code sensors.
The device can be used for food-borne pathogen detection, including detection of DNA fragments from Salmonella typhimurium and E. coli.
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