CRP Aptasensor Using Redox-Tagged DNA for Rapid Blood Detection
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Solution Overview
Problem
Current methods for detecting C-reactive protein (CRP) in clinical settings are time-consuming, require specialized equipment and personnel, and are not suitable for point-of-care applications, particularly in urgent cases like sepsis where rapid prognosis is critical.
Innovation Solution
A rapid, single-step, and reagentless electrochemical biosensor system using a screen-printed gold working electrode with redox-tagged CRP-targeting aptamers immobilized on its surface, combined with a platinum counter-electrode and a data processor for signal recording and processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electrochemical biosensor uses redox-tagged aptamer for CRP detection, then detection sensitivity reaches nanomolar level (5.4 mg/L), but device complexity increases due to electrode functionalization requirements
Solution Approach 1:
The patent applies preliminary action by pre-immobilizing redox-tagged aptamers onto the screen-printed gold electrode surface during device fabrication. This advance preparation eliminates the need for complex sample processing steps and multiple reagent additions during actual CRP detection, thereby achieving nanomolar sensitivity while simplifying the operational complexity of the device.
Solution Approach 2:
The patent uses redox-tagged aptamers as intermediary molecules that bridge the target analyte (CRP) and the electrochemical detection system. The aptamers specifically bind to CRP while the redox tags (methylene blue or ferrocene) transduce the binding event into measurable electrochemical signals, enabling sensitive detection without requiring complex labeling procedures.
2Measurement precision
If traditional immunoassay methods like ELISA are used for CRP detection, then measurement accuracy is maintained, but detection time extends to 2-3 hours requiring laboratory equipment and specialists
Solution Approach 1:
The patent extracts the essential detection function from complex laboratory-based ELISA systems by utilizing the inherent electrochemical activity of redox-tagged aptamers. This extraction eliminates the need for time-consuming washing steps, multiple reagent incubations, and specialized laboratory equipment, reducing detection time to minutes while maintaining accurate CRP quantification through direct electrochemical measurement.
Solution Approach 2:
The electrochemical biosensor implements self-service by using the electrochemical signal generated from the redox tags on the aptamers as the detection readout mechanism. This self-generated signal eliminates the need for external light sources, photodetectors, and complex signal processing systems required by traditional immunoassays, enabling rapid and accurate CRP detection in a simplified format.
3Reliability
If screen-printed gold electrode with alkane-thiol backfilling is used, then non-specific adsorption is prevented improving reliability, but manufacturing precision requirements increase
Solution Approach 1:
The patent employs screen-printed gold electrodes with alkane-thiol backfilling as disposable or single-use sensing elements. The pre-functionalized electrodes with blocked non-specific binding sites provide reliable CRP detection without requiring repeated surface regeneration or complex cleaning protocols, thereby ensuring detection reliability while reducing the burden of high-precision manufacturing and maintenance for each individual electrode.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system achieves CRP detection sensitivity up to 5.4 mg/L in human blood within 10 minutes, with a dynamic range of 1 mg/L to 50 mg/L in undiluted human blood, and is reusable for dose-response assays, significantly reducing the time and complexity of CRP detection.
Implementation Method 1
redox-tagged CRP-targeting aptamer immobilized on the surface of the gold working electrode
Implementation Method 2
current signal recorder connected to the screen-printed gold working electrode and the platinum counter-electrode
Implementation Method 3
thiolation of the aptamer and forming a gold-thiol bond between the thiolated aptamer and the surface of the gold working electrode
Implementation Method 4
aptamer immobilized on the surface of the gold working electrode
Implementation Method 5
back-filled with alkane-thiols to prevent non-specific adsorption
Data Source
AI summary
An electrochemical biosensing method using screen-printed gold electrodes functionalized with a redox probe modified DNA aptamer that binds specifically to CRP is provided. Binding-induced conformational switching of the CRP-targeting aptamer induces a specific and selective signal-ON event, which enables single-step and reagentless detection of CRP in as little as 1 minute. The aptasensor limit of detection spans approximately 20-60 nM in 50% human serum with dynamic response windows spanning 1-200 or 1-500 nM (R=0.97/R=0.98 respectively). The sensor also operates in undiluted human blood producing an LOD of 45 nM equating to 5.4 mg/L. The sensor is stable for at least 1 week and can be reused numerous times, as judged from repeated real-time dosing and dose-response assays.