Single Amplicon Activated Exclusion PCR for Droplet Barcoding
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Solution Overview
Problem
Existing methods for droplet barcoding in water-in-oil emulsions are limited by random Poisson dispersal of barcode templates, leading to undesirable empty or multi-barcode droplets, which result in lost cells and duplicated cell analysis.
Innovation Solution
A method involving the amplification of a single DNA template molecule in over 90% of droplets using a primer pair with distinct affinities and melting temperatures, ensuring each droplet contains a unique barcode, thereby overcoming Poisson statistics limitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If barcode templates are diluted into the aqueous solution for emulsion entry, then an accurate average number of barcoding templates per droplet can be reached, but the exact number of barcoding templates entering each droplet cannot be controlled with high precision due to Poisson statistics
Solution Approach 1:
The patent changes the physical state of barcode templates from dissolved molecules to suspended microparticles. This parameter change allows the templates to be distributed deterministically (one per droplet) rather than stochastically (Poisson distribution), resolving the contradiction between achieving accurate average concentration and controlling exact number per droplet.
Solution Approach 2:
The patent uses microparticles that carry barcode sequences as physical copies/carriers of the barcode information. These microparticles serve as tangible vehicles that can be precisely distributed into droplets, overcoming the limitations of distributing dissolved DNA molecules which follow Poisson statistics.
2Productivity
If droplets are prepared to contain an average density of one barcoding template per droplet, then throughput is maximized, but 36% of droplets will be empty and 36% will contain multiple templates
Solution Approach 1:
By changing from dissolved barcode templates to microparticle-based templates, the patent achieves deterministic distribution (one per droplet) instead of Poisson distribution. This eliminates empty droplets and multi-barcode droplets, resolving the contradiction between maximizing throughput and ensuring reliable single-cell barcoding accuracy.
Solution Approach 2:
The patent segments the barcode template into microparticle carriers that can be individually distributed. This segmentation allows precise control over the number of templates per droplet, ensuring each droplet receives exactly one template while maintaining high throughput.
3Productivity
If multiple barcodes are present in a single droplet, then more cells can be analyzed in parallel, but cells may be counted multiple times and downstream analysis cannot distinguish similar cells from duplicated cells
Solution Approach 1:
The patent changes the distribution parameter from Poisson (random) to deterministic (one per droplet). This ensures each droplet contains exactly one barcode template, eliminating multi-barcode droplets and the associated problem of cell duplication in analysis, while maintaining high parallel throughput through microparticle-based distribution.
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 approach significantly increases the proportion of droplets with a single barcode sequence, reducing empty and multi-barcode droplets, ensuring accurate and unique barcoding of cells, and enhancing the reliability of single-cell analysis.
Implementation Method 1
a first extension reaction with a first primer, on a template barcoded polynucleotide of the plurality of template barcoded polynucleotides to form a first extension molecule, wherein the extension efficiency of the first extension reaction is once per 2 cycles
Implementation Method 2
random Poisson dispersal of barcode templates into the droplets
Data Source
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AI summary
Provided herein are methods and compositions for activated amplification of a single template polynucleotide molecule, such as for cell barcoding and DNA sequencing.