Hairpin Molecule Extension for Barcoded Bead Library Preparation
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Solution Overview
Problem
The manufacturing of barcoded particles, such as DNA-barcoded hydrogel beads, is challenging due to the need for high numbers of input DNA oligonucleotide barcodes and the requirement for washing beads between steps to prevent non-specific reactions, leading to increased labor and reagent costs.
Innovation Solution
The method involves extending particle-associated oligonucleotides using hairpin molecules, where each hairpin molecule has a 3′ toehold domain complementary to the input primer, a paired stem domain with coupling and payload segments, and a hairpin loop domain. This process allows for the efficient and specific attachment of barcodes to particles without the need for washing between steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If ligation-based methods are used to attach barcodes to particles, then the attachment can be achieved, but the amount of input nucleic acid required is high
Solution Approach 1:
The patent uses hairpin molecules as intermediaries to facilitate barcode attachment. The hairpin molecules contain toehold domains that hybridize with input primers on particles, and paired stem domains that form stable duplexes with barcode sequences. This intermediary mechanism enables efficient barcode attachment with significantly reduced input nucleic acid requirements compared to direct ligation methods.
Solution Approach 2:
The patent changes the fundamental parameter of the attachment mechanism from chemical ligation to hybridization-based extension. By using hairpin molecules that undergo strand displacement through hybridization, the system achieves high efficiency barcode attachment with much lower input nucleic acid concentrations, transforming the reaction parameters to favor efficient extension over ligation.
2Reliability
If washing steps are included between steps to prevent non-specific reactions, then reaction specificity is improved, but labor and reagent costs increase
Solution Approach 1:
The patent enables continuous barcode attachment without interruption for washing steps. The hairpin molecule-based extension reaction proceeds continuously as the input primer on the particle hybridizes to the toehold domain, the polymerase extends through the paired stem domain, and the barcode is incorporated in a single uninterrupted process, eliminating the need for intermediate washing steps while maintaining specificity.
Solution Approach 2:
The hairpin molecule structure inherently provides specificity through its designed toehold and paired stem domains. The toehold domain ensures specific hybridization to the input primer, while the paired stem domain ensures specific extension only at the correct location. This self-verifying mechanism eliminates the need for external washing steps to remove non-specific reactions, as the reaction chemistry itself prevents non-specific binding.
3Reliability
If high numbers of input DNA oligonucleotide barcodes are used, then barcode attachment can be achieved, but reagent costs increase
Solution Approach 1:
The hairpin molecules serve as catalytic intermediaries that enable barcode attachment with minimal input nucleic acid. The toehold domain of the hairpin molecule hybridizes to the input primer, and the paired stem domain provides the template for barcode extension. This intermediary mechanism amplifies the signal, allowing successful barcode attachment with very low input nucleic acid concentrations, reducing the need for high numbers of input barcodes.
Solution Approach 2:
The patent changes the reaction parameters from ligation-based to hybridization-based extension. This parameter change enables the system to proceed with dramatically reduced input nucleic acid concentrations while maintaining high efficiency and reliability of barcode attachment, transforming the quantitative requirements from high input to low input regimes.
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 method significantly reduces the amount of input nucleic acid required, achieving at least a ten-fold reduction compared to ligation-based methods, and eliminates the need for washing, thereby decreasing labor and reagent costs while maintaining high efficiency and specificity.
Implementation Method 1
an unpaired first 3′ toehold domain complementary to the input primer
Implementation Method 2
a first paired stem domain formed by intramolecular nucleotide base pairing between a 3′ subdomain of the first hairpin molecule and a 5′ subdomain of the first hairpin molecule
Implementation Method 3
extending the input primer hybridized to the first 3′ toehold domain through the first paired stem domain of the first hairpin molecule, thereby displacing the 5′ subdomain of the first hairpin molecule
Data Source
AI summary
Disclosed herein include methods, compositions, and systems for extending particle-associated oligonucleotides. In some embodiments, the methods of extending particle-associated oligonucleotides enable efficient methods of preparing a library of barcoded beads. It is also provided, in some embodiments, hydrogel beads degradable upon application of a chemical stimulus that comprise releasably attached oligonucleotides.