Nanopore Sequencing Cell Osmotic Imbalance Stabilization

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Solution Overview

Problem

Nanopore-based sequencing systems face instability due to osmotic imbalances caused by ion flow through protein pores, leading to premature bilayer failure and nanopore ejection, which limits the longevity and efficiency of sequencing operations.

Innovation Solution

The method involves creating an initial osmotic imbalance by flowing an electrolyte solution with a different osmolarity than the well, counterbalancing the osmotic gradient to stabilize the lipid bilayer and extend nanopore lifetime, by adjusting the osmolarity ratio between the external reservoir and the well, thereby reducing structural strain on the bilayer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If an electrical bias is applied across the well and exterior reservoir to conduct ions through the protein pore, then sequencing function is enabled, but osmotic imbalance occurs leading to water diffusion and bilayer instability

Engineering Contradiction:
Improvesequencing functionVSAvoidbilayer stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary anti-action by introducing an osmolyte into the well before applying electrical bias. This osmolyte creates a counteracting osmotic pressure that prevents water diffusion caused by ion flow, thereby stabilizing the bilayer while enabling sequencing function. The osmolyte concentration is specifically chosen to balance the osmotic gradient created during sequencing operations.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The patent changes the osmotic parameter of the well by adding an osmolyte, thereby altering the osmotic balance between the well and exterior reservoir. This parameter change (increasing osmolarity in the well) counteracts the osmotic imbalance caused by preferential ion conduction during sequencing, stabilizing the system without affecting the sequencing capability.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If protein pores with unequal conductivity under positive and negative bias are used, then ion conduction for sequencing is achieved, but net ion influx or efflux occurs causing osmotic imbalance

Engineering Contradiction:
Improveion conduction capabilityVSAvoidelectrolyte concentration balance
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The osmolyte is introduced in advance to counteract the net ion flux that will occur during sequencing. By establishing an opposing osmotic gradient beforehand, the system compensates for the unequal conductivity of the protein pore under different bias conditions, maintaining electrolyte concentration balance while preserving ion conduction capability.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The patent converts the harmful effect of unequal ion conduction (which causes osmotic imbalance) into a beneficial situation by using the same preferential conduction property to create a predictable osmotic gradient, then counteracting it with an osmolyte. This approach transforms the inherent asymmetry of the protein pore into a manageable parameter rather than a defect.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Stability of the object's composition

If water diffusion occurs to balance electrolyte concentration, then osmotic equilibrium is achieved, but bilayer rupture or nanopore ejection occurs reducing operational lifetime

Engineering Contradiction:
Improveelectrolyte concentration equilibriumVSAvoidnanopore operational lifetime
Core Design Contradiction:
Stability of the object's compositionVSDuration of action of stationary object

Solution Approach 1:

The osmolyte is added before water diffusion can occur, creating a preemptive counterbalance to the osmotic gradient. This prevents the volume changes that would lead to bilayer rupture or nanopore ejection, thereby extending operational lifetime while still allowing electrolyte concentration equilibrium to be maintained through controlled means.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The osmolyte acts as a cushioning agent that absorbs the osmotic stress before it can cause damaging effects. By providing this protective buffer in advance, the system prevents bilayer rupture and nanopore ejection that would otherwise occur during water diffusion, extending the operational lifetime of the nanopore.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 significantly increases the longevity of nanopores and improves the efficiency of sequencing operations by maintaining bilayer integrity and preventing premature nanopore loss, allowing for more stable and prolonged sequencing processes.

Implementation Method 1

Such properties may lead to a net influx from or efflux into the well, which leads to diffusion of water through the PLB to balance the electrolyte concentration between the well and the external reservoir

Methodology Applied
Scientific EffectOsmosis: Osmosis

Data Source

PatentEP3475694B1Counteracting osmotic imbalance in a nanopore sequencing cell
Publication Date: 2024.07.24 F HOFFMANN LA ROCHE & CO AG
  • EP3475694B1 patent drawingFigure 1
  • EP3475694B1 patent drawingFigure 2
  • EP3475694B1 patent drawingFigure 3

AI summary

A method of analyzing a molecule is disclosed. A lipid bilayer (514) is formed (802) such that it divides a first reservoir (515) having a first reservoir osmolarity from a second reservoir (505) having a second reservoir osmolarity. An electrolyte solution (508) is flowed (806) to the first reservoir (515) that makes a first change to a ratio of the first reservoir osmolarity to the second reservoir osmolarity. A voltage is applied (812) across the lipid bilayer (514), wherein the lipid bilayer (514) is inserted with a protein nanopore (516), and wherein a net transfer of ions between the first reservoir and the second reservoir makes a second change to the ratio of the first reservoir osmolarity to the second reservoir osmolarity, and wherein the first change to the ratio and the second change to the ratio counter-balance each other.