Micropillar DNA Capture for Single Cell Genomic Amplification
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Solution Overview
Problem
Current methods for single cell genomic DNA isolation and amplification, such as multiple displacement amplification (MDA), suffer from random amplification bias due to chimera formation and non-linear enrichment, leading to underrepresentation of certain genome regions, especially in single cell analyses.
Innovation Solution
A microfluidic device with unique channel systems and DNA capture arrays containing micropillars is used for single cell genomic DNA isolation and amplification under flow conditions, enabling physical entanglement and immobilization of DNA for multiple rounds of amplification without chemical modification, thereby reducing bias.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple displacement amplification (MDA) is used for single cell WGA, then sufficient DNA quantity is obtained for sequencing, but random amplification bias occurs resulting in underrepresentation of certain genome regions
Solution Approach 1:
The invention segments the single cell into individual reaction chambers or droplets, isolating each cell's DNA amplification process. This segmentation prevents inter-cellular contamination and allows independent optimization of each reaction, improving both DNA yield and representation uniformity across the genome.
Solution Approach 2:
The invention introduces intermediary substances such as carrier RNA or DNA, and optimized buffer components that mediate the amplification process. These intermediaries facilitate more uniform primer binding across different genome regions, reducing amplification bias while maintaining sufficient DNA quantity for sequencing.
2Productivity
If conventional WGA methods are used, then amplification efficiency is achieved, but chimera formation and non-linear enrichment occur leading to amplification bias
Solution Approach 1:
The invention employs periodic action through multiple displacement amplification cycles with controlled timing and temperature changes. By carefully managing the periodic nature of primer annealing and extension steps, the method maintains high amplification efficiency while preventing chimera formation that occurs in continuous or poorly-controlled amplification processes.
Solution Approach 2:
The invention optimizes multiple parameters including temperature profiles, primer concentrations, and reaction time sequences. These parameter changes create conditions that favor specific primer binding to target sequences while minimizing non-specific binding and chimera formation, thereby improving amplification accuracy without sacrificing efficiency.
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 allows for uniform representation of the genome in amplified products, improving genome coverage and reducing amplification bias compared to conventional methods, enabling accurate single cell sequencing and genetic analysis.
Implementation Method 1
a DNA capture array positioned downstream of the cell capture site and comprising a plurality of micropillars configured and arranged in a manner effective for physically entangling and immobilizing thereon genomic DNA isolated from the captured single cell
Data Source
AI summary
The present invention relates to, inter alia, a microfluidic device for performing single cell genomic DNA isolation and amplification under flow. The microfluidic device comprises a solid substrate having one or more microfluidic channel system formed therein. Each microfluidic channel system of the microfluidic device comprises: (a) an intake region comprising a single microchannel; (b) a plurality of cell segregation microchannels; (c) a cell capture site located downstream of each cell segregation microchannel; and (d) a DNA capture array positioned downstream of the cell capture site and comprising a plurality of micropillars. Also disclosed is a whole genome amplification system that includes the microfluidic device of the present disclosure, as well as a method for conducting single cell DNA analysis via on-chip whole genome amplification while under flow, and a method for multiple displacement amplification (MDA) reactions of one or more nucleic acid sequence isolated single cells.