LO-HCR Analyte Detection in Autofluorescent Tissues
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Solution Overview
Problem
Existing methods for detecting analytes in samples, such as smFISH and HCR, face challenges with dim signals and high background fluorescence, particularly in autofluorescent tissues like FFPE samples, limiting the ability to detect analyte variability across large areas.
Innovation Solution
A method using linear oligo hybridization chain reaction (LO-HCR) with single-stranded monomers to generate polymeric products, allowing for efficient detection of analytes by amplifying signals and distinguishing them from background noise, even in autofluorescent tissues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If single molecule fluorescent in situ hybridization (smFISH) or hybridisation chain reaction (HCR) is used to detect analytes, then signal amplification is achieved, but background fluorescence remains high and signals remain dim, particularly in autofluorescent tissues
Solution Approach 1:
The detection system is segmented into distinct functional components: initiator oligos that bind to target RNA, HCR monomers that form polymeric signals, and fluorescent labels. This segmentation allows independent optimization of each component to improve signal while minimizing background interference from autofluorescent tissues.
Solution Approach 2:
The patent changes key parameters of the HCR system by using linear single-stranded monomers instead of traditional hairpin structures, and by using linear initiators instead of cyclic ones. These parameter changes result in faster reaction kinetics and brighter signals that outperform background fluorescence in autofluorescent tissues.
2Measurement precision
If high magnification imaging (60×-100×) is used to detect analytes, then detection precision is improved, but the imaged area is limited to very small regions (40-50 fields of view)
Solution Approach 1:
The patent changes the magnification parameter from high (60×-100×) to low magnification imaging. This parameter change is enabled by the use of LO-HCR which generates sufficiently bright signals that remain detectable at lower magnifications, thereby allowing imaging of much larger tissue areas while maintaining detection precision.
3Power
If traditional HCR with hairpin structures and metastable secondary structures is used, then signal amplification is achieved, but reaction kinetics are slow and variability depending on tissue type and sample conditions is high
Solution Approach 1:
The patent inverts the traditional HCR approach by using linear single-stranded monomers and linear initiators instead of hairpin structures with metastable secondary structures. This inversion eliminates the need for conformational changes and secondary structure formation, resulting in dramatically faster reaction kinetics while maintaining signal amplification capability.
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
LO-HCR provides robust and flexible analyte detection with improved signal amplification and specificity, enabling faster imaging and detection of analyte variability across larger sample areas, particularly in tissues with high autofluorescence.
Implementation Method 1
performing a linear oligo hybridization chain reaction (LO-HCR), wherein an initiator is contacted with a plurality of LO-HCR monomers of at least a first and a second species to generate a polymeric LO-HCR product hybridized to a target nucleic acid molecule
Data Source
AI summary
In some aspects disclosed herein are methods and compositions for detecting a target nucleic acid molecule, said method comprising performing a linear oligo hybridization chain reaction (LO-HCR) to generate a polymeric product, and detecting the polymeric product, thereby detecting the target nucleic acid molecule.