Conformation-Switching Aptamers for Cortisol Biosensing
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Solution Overview
Problem
There is a need for improved cortisol-binding aptamers that undergo a conformational change when binding or unbinding cortisol at physiologically relevant concentrations, and that can be incorporated into aptamer-based sensors for real-time, continuous monitoring of cortisol.
Innovation Solution
The development of optimized aptamers, such as those represented by SEQ IDs 1-24, which are short single-stranded DNA sequences truncated and mutated to enhance cortisol binding affinity and structure switching capability in biofluids. These aptamers can be functionalized with a redox reporter and immobilized onto sensor surfaces for electrochemical detection of cortisol.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional aptamers are used for cortisol detection, then they can bind cortisol, but they do not undergo sufficient structural changes in the absence of the capture strand and require further optimization to maximize signal output
Solution Approach 1:
The patent applies dynamics by designing aptamers that undergo conformational changes from an open to a closed state upon cortisol binding. This dynamic structural transition enables the aptamer to move the reporter group closer to the electrode surface, maximizing signal output without requiring additional optimization steps. The conformational flexibility is built into the aptamer sequence itself, allowing it to adapt its structure based on target presence.
2Measurement precision
If capture SELEX is used to identify cortisol binding aptamers, then cortisol binding aptamers can be identified, but the sensitivity in biofluids is insufficient for detecting cortisol at physiological concentrations
Solution Approach 1:
The patent applies parameter changes by systematically optimizing aptamer sequences through multiple rounds of SELEX enrichment specifically in biofluid matrices. This process selects for aptamers with enhanced binding affinity and conformational switching capability that function effectively at physiological cortisol concentrations. The optimization parameters include binding strength, structural flexibility, and resistance to biofluid interference, resulting in aptamers with detection sensitivity sufficient for physiological monitoring.
3Reliability
If aptamers are truncated and mutated to enhance binding affinity, then cortisol binding affinity improves, but the process relies largely on trial and error
Solution Approach 1:
The patent applies preliminary action by performing comprehensive structural characterization and binding assays on aptamer candidates before full-scale production. The SELEX process pre-enriches for high-affinity binders, and subsequent optimization steps systematically test truncations and mutations. This preliminary screening and characterization approach reduces reliance on trial-and-error by identifying promising candidates early, allowing focused optimization on a smaller set of proven sequences.
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 optimized aptamers demonstrate improved binding affinity and structure switching capability, enabling effective real-time, continuous monitoring of cortisol levels in biofluids, even at physiological concentrations.
Implementation Method 1
Structure-switching aptamers (SSA) are utilized as the bio-recognition element in EAB sensing platforms due to their ability to undergo a conformational change in the presence of target molecule, thereby moving a redox reporter close to or away from the surface of an electrode
Implementation Method 2
Electrochemical, aptamer-based (EAB) sensors have the capability to support continuous, real-time monitoring of specific target molecules in complex biofluids
Data Source
AI summary
Aptamers, biosensors and aptamer-based biosensors for monitoring cortisol and other hormones are provided. Methods of optimizing aptamers for biosensing applications are also provided. Aptamers have been optimized to undergo a conformational change when binding, or unbinding, cortisol at physiologically relevant concentrations. These aptamers can be incorporated into aptamer-based sensors for real-time, continuous monitoring of cortisol.