Nanoswitch Single-Molecule Detection in Complex Fluids
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Solution Overview
Problem
Current protein detection methods, such as ELISA, face limitations in sensitivity, especially for proteins present at low concentrations in complex biological fluids, and existing single-molecule techniques suffer from low throughput and unspecific adhesive forces, making it challenging to detect proteins early in infections like Zika and Ebola.
Innovation Solution
A novel single-molecule detection technique using force-controlled nanoswitches, where nucleic acid constructs undergo conformational changes upon binding to specific analytes, allowing for attomolar sensitivity detection by measuring the length or rupture force of surface-tethered nanoswitches under controlled force, distinguishing between specific and non-specific binding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ELISA methods are used for protein detection, then the detection process is simple and accessible, but the sensitivity is insufficient for detecting proteins at low concentrations
Solution Approach 1:
The detection system is segmented into multiple functional components: surface-tethered nanoswitches with specific analyte-binding agents, force application mechanisms, and measurement systems. This segmentation allows each component to be optimized independently, achieving high sensitivity through single-molecule detection while maintaining operational simplicity through modular design
Solution Approach 2:
Nanoswitches serve as intermediary elements that translate analyte binding events into measurable mechanical signals. These nanoswitches act as mediators between the analyte molecules and the detection system, enabling sensitive detection through conformational changes that can be read out mechanically
2Measurement precision
If standard single-molecule techniques are used, then single-molecule resolution is achieved, but throughput is low and unspecific adhesive forces cause false positives
Solution Approach 1:
The system segments the detection field into multiple independent measurement zones with surface-tethered nanoswitches, enabling parallel observation of thousands of single-molecule events simultaneously. This segmentation increases throughput while maintaining single-molecule resolution through spatial distribution of detection events
Solution Approach 2:
The nanoswitches are designed with local quality variations: specific analyte-binding agents at one end for specific binding, and surface-tethering moieties at the other end for stable attachment. This local differentiation enables specific analyte recognition while preventing nonspecific adhesive forces through controlled interaction sites
3Speed
If solution-based DNA origami constructs are used for detection, then fast reaction kinetics are achieved, but nonspecific adhesive forces lead to high false positive rates
Solution Approach 1:
The system extracts the binding reaction from the bulk solution phase and anchors it to a solid surface through tethered nanoswitches. This extraction removes the confounding factor of nonspecific adhesive forces present in solution-based methods, as the surface-tethered configuration provides a controlled environment where only specific analyte-nanoswitch interactions are detected
Solution Approach 2:
The nanoswitches are pre-prepared and tethered to the surface before analyte introduction, with analyte-binding agents already positioned for immediate interaction. This preliminary arrangement enables fast reaction kinetics upon analyte arrival while the pre-established surface tethering prevents nonspecific adhesion issues
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
This method achieves a nominal limit of detection of 0.4 attomolar for DNA in buffer and 13 femtomolar for prostate-specific antigen in whole blood, significantly improving sensitivity and specificity compared to conventional methods.
Implementation Method 1
The nanoswitches undergo a conformation change upon binding to a specific analyte
Implementation Method 2
parallel stretching of thousands of surface-tethered nanoswitches under force, such as hydrodynamic flow
Implementation Method 3
contacting a sample with a plurality of nanoswitches for a time and under conditions sufficient for binding of an analyte to its respective nanoswitch(es)
Data Source
AI summary
Provided herein are methods and products for detecting analytes in a sample. The analytes may be rare analytes such as biomarkers in a biological sample. These methods make use of nucleic acid nanoswitches that adopt a particular conformation and have a particular length in the presence of an analyte.