Microfluidic Probe Bypass Channel for Aperture Blockage

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Microfluidic probes face challenges with partial or complete blockage of apertures during surface processing, leading to uncontrollable liquid escape and contamination, especially when scanning surfaces with topographical variations.

Innovation Solution

A microfluidic probe design incorporating a bypass channel that connects the injection and aspiration channels, along with a control channel, allows for hydrodynamic flow confinement and diversion of processing liquid in case of blockage, maintaining liquid confinement and preventing contamination by adjusting hydraulic resistances and flow paths.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a microfluidic probe processes surfaces with topographical variations, then the probe can handle diverse surface conditions, but aperture blockage occurs leading to liquid escape and contamination

Engineering Contradiction:

Improveability to process surfaces with topographical variationsVSAvoidaperture blockage leading to liquid escape

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The liquid transport path is segmented into multiple independent channels: a primary liquid injection channel, a bypass channel, and a liquid aspiration channel. This segmentation allows the system to switch between normal operation (through primary channels) and failure mode (through bypass channel) when aperture blockage occurs, maintaining reliability while preserving adaptability to various surface topographies

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The bypass channel acts as an intermediary pathway that connects the liquid injection channel to the liquid aspiration channel. When the primary apertures are blocked during processing of surfaces with topographical variations, the bypass channel provides an alternative route for liquid flow, preventing uncontrolled liquid escape and contamination while allowing the probe to continue operating on diverse surface conditions

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the probe maintains hydrodynamic flow confinement, then liquid confinement is improved, but the system becomes vulnerable to blockage failures

Engineering Contradiction:

Improvehydrodynamic flow confinementVSAvoidvulnerability to blockage failures

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The bypass channel is designed with specific hydraulic resistance characteristics beforehand to cushion against failure. The hydraulic resistance of the bypass channel is calibrated to be higher than the primary liquid transport path during normal operation, preventing unnecessary flow diversion. However, when blockage occurs, this pre-designed resistance characteristic ensures controlled flow through the bypass channel, maintaining liquid confinement and preventing catastrophic failure

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If a bypass channel is added to prevent blockage failures, then reliability improves, but device complexity increases

Engineering Contradiction:

Improverobustness against aperture blockagesVSAvoidadditional bypass and control channels

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The bypass channel is merged with the existing liquid injection and aspiration channels to form an integrated fluidic network. The bypass channel connects directly to the liquid injection channel at a first junction and to the liquid aspiration channel at a second junction, creating a unified system where the bypass functionality is embedded within the primary liquid transport path rather than being a separate, complex subsystem

Inventive Principle:

Principle #5Merging (Combining)

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

The design enhances the robustness of microfluidic probes against aperture blockages, ensuring reliable operation and preventing liquid escape, even with varying probe-to-surface distances and particulate contamination, by passively reconfiguring flow paths and maintaining hydrodynamic flow confinement.

Implementation Method 1

the hydraulic resistance of the first portion of the bypass channel is larger than the hydraulic resistance of the second portion of the bypass channel

Methodology Applied

Scientific EffectHydraulic resistance: Pressure Drop

Implementation Method 2

assuming a suitable liquid/pressure flow is applied to the control channel

Methodology Applied

Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 3

The probe is preferably designed so as to allow a hydrodynamic flow confinement of processing liquid injected through the first aperture and aspirated from the second aperture

Methodology Applied

Scientific EffectHydrodynamic flow confinement: Laminar Flow

Data Source

PatentUS10507465B2Microfluidic probe with bypass and control channels

Publication Date: 2019.12.17 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

A microfluidic probe includes a probe head with a processing surface that includes a first aperture and a second aperture. The probe further includes a liquid injection channel, which leads to the first aperture, and a liquid aspiration channel, which extends from the second aperture. The probe also includes a bypass channel, arranged so as to fluidly connect the liquid injection channel to the liquid aspiration channel, as well as a control channel. The latter fluidly connects to the bypass channel, hence forming a junction therewith, so as to define two portions of the bypass channel. These portions includes: a first portion that extends from the junction to the liquid injection channel; and a second portion that extends from that same junction to the liquid aspiration channel. The invention is further directed to methods of operation of a probe as described above, to process a surface.