PH sensing technique based on graphene electrodes
Inventors
Johnson, Jr., Alan T • PING, Jinglei
Assignees
University of Pennsylvania Penn
Publication Number
US-12392747-B2
Publication Date
2025-08-19
Expiration Date
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Abstract
Provided are devices and methods for a rapid, non-perturbative and energy-efficient technique for pH sensing based on a flexible graphene electrode. This technique does not require the application of gate voltage or source-drain bias, and demonstrates fast pH-characterization with precision. The disclosed technology is suitable for in vivo monitoring of tumor-induced pH variation in tissues and detection of pH changes as required in a DNA sequencing system.
Core Innovation
Provided are devices and methods for a rapid, non-perturbative and energy-efficient technique for pH sensing based on a flexible graphene electrode. This technique does not require the application of gate voltage or source-drain bias, and demonstrates fast pH-characterization with precision. Disclosed is a technique for measuring low-level Faradaic charge-transfer current across the graphene/solution interface via real-time charge monitoring of graphene microelectrodes in ionic solution, enabling the development of flexible and transparent pH sensors that are useful in, inter alia, in vivo applications.
Accurate and in vivo measurement of pH is vital for medical diagnosis, treatment, and health care, and tumors tend to be more acidic than normal tissues. pH sensors based on conventional materials such as glass and silicon suffer from large size, slow response, mechanical fragility, and size-limitation, and accordingly there is a need in the art for improved pH measurement methods and improved pH measurement devices. The disclosed graphene-based sensors avoid the hazards presented by traditional glass-based pH meters, have a flexible and scalable design, and include aspects such as low level signal measure, high sensitivity, being a non-FET device, being less prone to artifacts, and having no current flow to confound measurements.
Claims Coverage
The patent includes one independent claim. The independent claim discloses multiple inventive features relating to paired graphene electrodes and a processing train configured to measure and determine electronic characteristics from Faradaic charge transfer.
First graphene electrode in electric communication with a conductive contact
A first graphene electrode in electric communication with a first conductive contact.
Second graphene electrode in electric communication with a conductive contact
A second graphene electrode in electric communication with a second conductive contact.
Processing train configured to measure Faradaic charge transfer
A processing train configured to measure Faradaic charge transfer between each graphene electrode and a sample in contact with that graphene electrode.
Determination of electronic characteristic from Faradaic charge transfer
The processing train determining an electronic characteristic of each sample from the Faradaic charge transfer between the corresponding graphene electrode and the corresponding sample.
The independent claim covers a sensor device comprising paired graphene electrodes each electrically coupled to respective conductive contacts, and a processing train that measures Faradaic charge transfer at each electrode-sample interface and determines electronic characteristics of the samples from those Faradaic measurements.
Stated Advantages
Rapid, fast pH-characterization with precision (readout in seconds).
Non-perturbative operation that does not require application of gate voltage or source-drain bias, yielding ultra-low-power operation.
Flexible and scalable design that is biocompatible and avoids hazards of glass-based pH meters.
High sensitivity and low-level signal measurement (direct Faradaic charge measurement) and being a non-FET device less prone to artifacts.
Reversible signal and better reversibility than graphene FETs.
Documented Applications
In vivo monitoring of tumor-induced pH variation in tissues.
Detection of pH changes as required in a DNA sequencing system, including application to DNA amplification and detection.
Testing of biological samples in vitro and ex vivo, including obtaining readings on small-volume samples.
Real-time monitoring of the pH of tissues and potential insertion of a device into a subject such that the device contacts a fluid or other tissue of interest within the subject.
Monitoring of gastric pH.
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