Nanopore Sequencing Cell Calibration for Voltage Drift
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Solution Overview
Problem
Nanopore-based sequencing chips face challenges in accuracy and stability due to manufacturing variability, time-dependent non-idealities, and biochemical circuit characteristics, leading to difficulties in determining correct nucleotides and maintaining consistent output voltages.
Innovation Solution
The implementation of techniques for characterizing and calibrating nanopore sequencing cells, including physical checks, zero-point calibration, nanopore formation, and signal normalization, to ensure consistent and accurate nucleotide detection by modeling cell elements as discrete resistive and capacitive components and applying normalization factors to correct for cell-specific non-idealities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If nanopore sequencing chips are manufactured with large numbers of sensor cells, then productivity increases, but manufacturing precision and measurement precision deteriorate due to variability
Solution Approach 1:
The patent divides the sequencing chip into multiple independent sensor cells arranged in an array, where each cell contains its own nanopore and measurement circuitry. This segmentation allows parallel sequencing of multiple DNA strands simultaneously, increasing overall productivity while isolating manufacturing variability to individual cells rather than affecting the entire system.
Solution Approach 2:
The patent implements calibration procedures that measure and adjust voltage parameters for each individual sensor cell. By characterizing the electrical characteristics of each cell and applying cell-specific calibration factors, the system compensates for manufacturing variability and maintains measurement precision across large arrays of sensor cells.
2Ease of manufacture
If conventional semiconductor manufacturing techniques are used, then ease of manufacture improves, but reliability deteriorates due to biochemical circuit element variability
Solution Approach 1:
The patent incorporates calibration and characterization steps into the manufacturing process itself, performing measurements and adjustments before the sequencing operation begins. This preliminary action allows the system to account for and compensate for biochemical variability in advance, ensuring reliable operation without requiring complex real-time adjustments during sequencing.
Solution Approach 2:
The patent implements feedback mechanisms where the electrical characteristics of each sensor cell are measured and used to adjust operating parameters. This feedback loop compensates for variability in biochemical circuit elements, maintaining consistent performance across different cells and over time despite the inherent variability of lipid bilayers and nanopores.
3Measurement precision
If voltage measurements are taken without calibration, then measurement precision is maintained, but reliability deteriorates due to time-dependent non-idealities
Solution Approach 1:
The patent performs zero-point calibration and characterization measurements before the actual sequencing operation. This preliminary calibration establishes baseline voltage levels and detection thresholds for each cell, ensuring that subsequent measurements are accurate and consistent. The calibration is performed at the same time point as the sequencing measurement to account for temporal drift.
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 enhances the accuracy and stability of nucleotide detection by ensuring consistent output signals and improving base detection capabilities, reducing errors and spurious signals, and maintaining the integrity of sequencing data over time.
Implementation Method 1
When a voltage potential is applied across a nanopore immersed in a conducting fluid, a small ion current attributed to the conduction of ions across the nanopore can exist.
Implementation Method 2
The size of the current is sensitive to the pore size and which molecule in the nanopore. A voltage in a circuit including the nanopore can be measured (e.g., at an integrating capacitor) as a way of measuring the resistance of the molecule
Data Source
AI summary
Improved multi-cell nanopore-based sequencing chips and methods can employ formation, characterization, calibration, and/or normalization techniques. For example, various methods may include one or more steps of performing physical checks of cell circuitry, forming and characterizing a lipid layer on the cells, performing a zero point calibration of the cells, forming and characterizing nanopores on the lipid layers of each cell, performing a sequencing operation to accumulate sequencing signals from the cells, normalizing those sequencing signals, and determining bases based on the normalized sequencing signals.