Durable enzyme-based biosensor and process for drop deposition immobilization
Inventors
Assignees
Northeastern University Boston
Publication Number
US-12213784-B2
Publication Date
2025-02-04
Expiration Date
2037-12-11
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Abstract
A sensor having improved shelf life is provided for determining concentration of a biomarker in a liquid sample. The sensor functions by electrochemical detection and requires use of a biomolecule, e.g., an enzyme that catalyzes an electron transfer reaction specific for the biomarker. The sensor requires use of a quaternary ammonium compound as a bio-linker. It further requires crosslinking of the biomolecule for improved stability.
Core Innovation
The invention provides a robust, stable biosensor platform based on an electrochemical device containing a cross-linked biomolecule, such as an enzyme, for the sensitive and specific detection and quantification of biomarkers in liquid samples. The working electrode is coated with nanomaterial sensor elements and a functionalization coating comprising a quaternary ammonium compound (acting as a bio-linker), metal nanoparticles, and a crosslinked enzyme that catalyzes an electron transfer reaction specific for the biomarker.
This biosensor is fabricated using a drop deposition immobilization process, in which a suspension containing the quaternary ammonium compound, metal nanoparticles, and enzyme is deposited onto the sensor elements. The enzyme is crosslinked with a reagent (e.g., glutaraldehyde or other crosslinkers), providing improved structural stability and enhanced shelf life, while quaternary ammonium compounds in the functionalization layer serve to further increase sensor sensitivity and longevity.
The background states that traditional enzyme-based biosensors suffer from short shelf life due to the lability of enzymes, limiting their utility as reliable disease monitoring devices. The present technology addresses this problem by stabilizing enzymes via crosslinking and using quaternary ammonium bio-linkers, resulting in biosensors with substantially increased shelf stability (typically a year or more) for real-time assessment of health or disease diagnosis.
Claims Coverage
The patent contains four independent claims, each directed to a principal inventive feature: the biosensor device, the biomarker analysis system, the method of determining biomarker concentration, and the method of fabricating the biosensor.
Biosensor device with crosslinked enzyme and quaternary ammonium compound via drop deposition
A sensor for determining the concentration of a biomarker in a liquid sample, comprising: - An insulating or semiconducting substrate with at least one working electrode, counter electrode, and reference electrode, each with a conductive metal layer. - A sample placement area on the substrate where the working electrode is coated with sensor elements functionalized with a coating containing a quaternary ammonium compound, metal nanoparticles, and a crosslinked enzyme that catalyzes an electron transfer reaction specific for the biomarker. - All electrodes are connected to an amperometry circuit that measures electron transfer into the working electrode, with output voltage correlating to biomarker concentration. - The functionalization coating is fabricated via drop deposition from a single suspension comprising the quaternary ammonium compound, metal nanoparticles, and enzyme.
Biomarker analysis system including the sensor and signal processing device
A biomarker analysis system comprising the biosensor device as described, and a signal conditioning and/or analysis device that processes the electrical signal generated by the sensor.
Method for determining biomarker concentration using functionalized biosensor
A method including the steps of: 1. Providing a sensor as described above, fabricated by drop deposition of a single suspension containing quaternary ammonium compound, metal nanoparticles, and enzyme. 2. Introducing a liquid sample into the sensor's sample placement area. 3. Determining the concentration of the biomarker from the electrical output of the sensor.
Method of fabricating the biosensor by drop deposition and enzyme crosslinking
A fabrication method comprising: 1. Microfabricating one or more working, reference, and counter electrodes on an insulating substrate. 2. Depositing sensor elements onto the working electrode. 3. Depositing a functionalization coating onto the sensor elements, where the coating comprises one or more layers and each layer has a quaternary ammonium compound, metal nanoparticles, and a biomarker-specific enzyme. All layers are deposited by drop deposition of a single suspension containing these components. 4. Crosslinking the enzyme by applying a crosslinking reagent to the functionalization coating.
The independent claims define a biosensor and associated systems and methods characterized by the integration of a crosslinked enzyme, quaternary ammonium compound, and metal nanoparticles in a functionalized coating deposited by drop deposition, enabling stable and sensitive electrochemical biomarker detection.
Stated Advantages
The biosensor has improved shelf life, with shelf stability of one year or more.
The sensor provides robust and stable detection of biomarkers in liquid samples.
The biosensor exhibits high sensitivity and specific detection and quantification capability.
The technology overcomes the short shelf life limitations of traditional enzyme-based biosensors.
The fabrication method allows formation of a stable, functionalized biosensor coating through a simple drop deposition process.
The use of quaternary ammonium compounds in the coating results in enhanced shelf life and improved sensitivity.
Documented Applications
Determining the concentration of glucose in saliva for noninvasive glucose monitoring.
Real-time, point-of-care (POC) assessment of disease-associated biomarkers for diagnosis or health monitoring.
Biomarker monitoring technology for chronic disease management enabling real-time measurement of health conditions.
Use in systems for monitoring disease-associated biomarkers at home and around the clock, including triggering alarms for abnormal glucose levels.
Potential integration with automated insulin delivery systems, such as artificial pancreas or insulin pumps, for feedback-controlled insulin administration.
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