Microfluidic Droplet Sequencing for Nucleotide Detection
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Solution Overview
Problem
Current nucleotide sequencing methods are limited in their ability to efficiently determine the sequence of nucleotide bases in polynucleotides, as they often rely on detectable elements that are not specifically activated by biochemical or enzymatic reactions, leading to suboptimal detection sensitivity and specificity.
Innovation Solution
A microfluidic device that generates a stream of droplets containing single nucleotides, where each droplet is treated with biological probes having undetectable detectable elements that are activated upon binding to their complementary nucleotides, allowing for the release of detectable elements in a specific state, enabling precise fluorescence detection of the nucleotide sequence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional sequencing methods use detectable elements without specific activation, then the sequencing process can proceed, but the detection sensitivity and specificity are suboptimal
Solution Approach 1:
The patent applies preliminary action by pre-attaching detectable elements (fluorophores) to nucleotides before the sequencing reaction. These detectable elements remain dormant until the nucleotide is incorporated into the growing polynucleotide chain by DNA polymerase, at which point they become activated and emit detectable signals. This preliminary attachment ensures that detection only occurs when and where the nucleotide is actually incorporated, thereby improving detection sensitivity and specificity without requiring complex real-time activation mechanisms.
Solution Approach 2:
The patent utilizes parameter changes by employing fluorophores with distinct emission wavelengths (spectral parameters) that change based on the specific nucleotide incorporated. Each type of nucleotide (A, T, C, G) is labeled with a fluorophore having a characteristic emission spectrum, allowing the detection system to distinguish between different nucleotides by detecting the wavelength of emitted light. This parameter-based differentiation improves measurement precision while maintaining relatively simple detection hardware.
2Measurement precision
If detectable elements are activated upon binding to complementary nucleotides, then sequencing accuracy improves, but the biochemical reaction complexity increases
Solution Approach 1:
The patent applies self-service by designing a system where the DNA polymerase enzyme naturally performs the activation function. As DNA polymerase incorporates labeled nucleotides into the growing polynucleotide chain, it automatically triggers the activation of fluorophores through the biochemical reaction itself. The enzyme's catalytic action on the nucleotide substrate inherently activates the detectable element, eliminating the need for separate activation steps or additional complex biochemical reagents. This self-service mechanism improves sequencing accuracy while minimizing the increase in biochemical reaction complexity.
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 enhances the sensitivity and specificity of nucleotide sequencing by ensuring that detectable elements are only activated when bound to their complementary nucleotides, resulting in a clear and characteristic fluorescence signal that accurately represents the nucleotide sequence, improving the accuracy of sequencing outcomes.
Implementation Method 1
causing the detectable element to be released from the used probe in a detectable state... enabling precise fluorescence detection of the nucleotide sequence
Implementation Method 2
introducing into each droplet a plurality of biological probe types each type comprising a different detectable element in an undetectable state and (ii) being adapted to capture a different complimentary single nucleotide
Data Source
Figure 1
AI summary
Disclosed is a microfluidic device for sequencing a nucleic acid characterised by comprising: • a first zone in which the analyte is contained and progressively digested into a stream of its constituent single nucleotides; • a primary microfluidic pathway connected to the first zone adapted to allow passage of a carrier solvent containing an ordered stream of primary aqueous microdroplets at least some of which contain one of the single nucleotides; • a second zone disposed within the primary microfluidic pathway and comprising a microdroplet injector and/or a coalescence means for sequentially coalescing secondary aqueous microdroplets from a secondary microfluidic pathway into the primary aqueous microdroplets in the ordered stream; • a storage zone connected to the primary microfluidic pathway downstream of the second zone(s) where the primary aqueous microdroplets are stored; • a light source for interrogating the microdroplets at one or more locations downstream of the primary microfluidic pathway and • a photodetector for detecting fluorescence from the primary aqueous droplets at the location(s).