Fractionally Labeled Nucleotides for Sequencing

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Solution Overview

Problem

Nucleic acid sequencing methods using luminescent components face challenges due to radiation damage, leading to reduced sequence read length and accuracy, particularly in extended detection cycles, as luminescence can cause degradation of nucleic acids.

Innovation Solution

A method involving fractionally labeled nucleotides is employed, where the fraction of exogenously labeled nucleotides is increased over cycles, minimizing local concentration of damaging free radicals and reducing photodamage by adjusting the label fraction in nucleic acid sequencing processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If luminescent components are used for nucleic acid sequencing detection, then detection specificity is improved, but radiation damage to nucleic acids increases leading to reduced sequence read length and accuracy

Engineering Contradiction:
Improvedetection specificityVSAvoidradiation damage
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent implements periodic action by using intermittent illumination during sequencing cycles rather than continuous exposure. The system alternates between illumination periods for signal detection and dark periods for nucleic acid recovery, allowing the nucleic acids to rest from radiation exposure while maintaining detection capability during illuminated phases.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent applies parameter changes by dynamically adjusting illumination intensity and exposure duration throughout the sequencing process. The system varies these parameters to optimize the balance between obtaining sufficient signal for accurate base calling and minimizing cumulative radiation damage to the nucleic acids.

Inventive Principle:
Principle #35Parameter changes

2Duration of action of moving object

If extended detection cycles are used for complete sequencing, then sequence read length is improved, but cumulative radiation damage increases reducing accuracy

Engineering Contradiction:
Improvesequence read lengthVSAvoidsequence read accuracy
Core Design Contradiction:
Duration of action of moving objectVSReliability

Solution Approach 1:

The patent uses periodic action with structured illumination cycles that include both detection phases and rest phases. This allows extended sequencing to be performed while periodically reducing radiation exposure, preventing cumulative damage that would otherwise degrade sequence read accuracy over time.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent implements dynamics by making the illumination regime adaptive throughout the sequencing process. The system dynamically adjusts illumination parameters based on the sequencing progress and observed nucleic acid integrity, allowing extended read lengths while maintaining accuracy through real-time parameter optimization.

Inventive Principle:
Principle #15Dynamics

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 helps preserve nucleic acids, maintaining signal purity and extending sequence read length by reducing radiation-induced damage, while maintaining detection sensitivity.

Implementation Method 1

Luminescent analytes, when exposed to light of an appropriate wavelength, will emit luminescence that can be detected using any of a variety of optical detection devices

Methodology Applied
Scientific EffectLuminescence: Luminescence

Implementation Method 2

light is a form of electromagnetic irradiation that can cause damage to the samples

Methodology Applied
Scientific EffectPhotodamage: Photo-oxidation

Data Source

PatentEP3924513B1Mitigating adverse impacts of detection systems on nucleic acids and other biological analytes
Publication Date: 2023.04.12 PACIFIC BIOSCIENCES OF CALIFORNIA INC

AI summary

A method for sequencing a population of nucleic acids, which includes (a) binding the population of nucleic acids with a fractionally labeled mixture of nucleotides, thereby forming a fractionally labeled population of nucleic acids, wherein the mixture includes nucleotide cognates for a common base type in the templates, and wherein a fraction of the nucleotide cognates for the common base type in the mixture are exogenously labeled nucleotides that produce a signal that is not produced by other nucleotide cognates for the common base type in the mixture; (b) detecting the signal from the fractionally labeled population of nucleic acids; and (c) repeating (a) and (b) using a second mixture of the fractionally labeled nucleotides, wherein the fraction of the exogenously labeled nucleotides is higher in the second mixture.