Rib-Adapted Surfaces Shield Particles from Draining Meniscus Shear
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Solution Overview
Problem
Existing methods for separating particles from a bulk liquid often result in the shear-off of particles due to forces exerted by a draining meniscus, which can damage particles and reduce the efficiency of particle recovery, particularly in cell biology applications where selective forces are used to concentrate cells.
Innovation Solution
The use of rib-adapted surfaces with a plurality of ribs spaced apart to capillarily retain a portion of the bulk liquid and particles, forming a liquid film that shields particles from the forces of the draining meniscus, thereby reducing shear-off and improving particle recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If bulk liquid is removed away from the surface during particle separation, then separation efficiency is improved, but particles in contact with the surface are damaged by shear forces from the draining meniscus
Solution Approach 1:
The surface is segmented into multiple regions by forming a monolayer of particles at the gas-liquid interface, creating distinct zones that can be selectively manipulated during liquid removal
Solution Approach 2:
A magnetic field is introduced as an intermediary force to hold particles at the surface during liquid removal, counteracting the harmful shear forces from the draining meniscus and enabling efficient separation without particle damage
2Manufacturing precision
If particles are concentrated at the surface for separation, then separation effectiveness is improved, but particle recovery is reduced due to shear-off during liquid removal
Solution Approach 1:
A magnetic force is applied to counterbalance the shear forces exerted by the draining meniscus on surface particles, preventing particle loss while maintaining concentration at the interface for effective separation
3Ease of operation
If manual pour-off or automated pipetting is used for liquid removal, then particle separation can be performed, but variance in separation performance increases and recovery values decrease
Solution Approach 1:
The mechanical liquid removal process is supplemented with magnetic field control to retain particles at the surface, reducing the impact of operator variability and improving consistency of separation performance across different operations
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 particle separation by increasing recovery values, reducing variance in separation performance, enabling effective separation at low particle numbers, and reducing cell damage, while also allowing for faster separation times.
Implementation Method 1
a space between a first rib and a second rib spaced apart from the first rib by a pitch distance and dimensioned to capillarily retain therebetween a portion of the bulk liquid
Implementation Method 2
Liquid-surface interactions dictate that a meniscus may form where a bulk liquid comes into contact with a surface at the gas-liquid-solid interface
Data Source
AI summary
Surfaces contactable by a bulk liquid for use in particle isolation are described. The surfaces comprise a plurality of ribs spaced apart to capillarily retain a portion of the bulk liquid and particles of interest therebetween. Collectively, the portion of the bulk liquid retained by the plurality of ribs on the surface forms a liquid film. The one or more particles received within the space and enveloped by the liquid film may be protected from one or more forces exerted by a draining meniscus passing over the surface.