Narrow Angle Pipette Tip for Low Volume Dispensing
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Solution Overview
Problem
Existing pipettes face challenges in achieving high velocity for non-contact dispensing of small liquid volumes due to wide angle tip geometries, leading to poor dispense performance and dead volumes, especially at low source and dispensing volumes.
Innovation Solution
A pipette tip with an inner wall surface extending at an angle of at most 5 degrees relative to the longitudinal axis, enabling controlled introduction of airgaps for improved liquid attachment and handling of low volumes, and allowing for pre- and post-sample airgap mechanisms to minimize dead volume and enhance dispensing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a wide angle pipette tip geometry is used, then the tip can accommodate larger liquid volumes, but the liquid cannot achieve high enough velocity for non-contact dispensing of small volumes
Solution Approach 1:
The patent applies parameter changes by modifying the tip angle geometry from a conventional wide angle to a narrow angle of at most 5 degrees. This geometric parameter change enables the liquid to achieve the necessary high velocity for non-contact dispensing while maintaining compatibility with small liquid volumes, directly resolving the contradiction between liquid velocity and tip geometry.
2Speed
If the plunger stroke is increased to achieve high liquid velocity, then non-contact dispensing becomes possible, but the tip geometry becomes more complex
Solution Approach 1:
Instead of increasing the plunger stroke length, the patent changes the tip angle parameter to at most 5 degrees. This alternative parameter modification achieves the same goal of high liquid velocity for non-contact dispensing while avoiding the complexity that would arise from a longer plunger stroke, thus resolving the contradiction between liquid velocity and device complexity.
3Measurement precision
If a narrow angle tip is used to improve liquid velocity, then small volumes can be handled effectively, but the manufacturing precision requirements increase
Solution Approach 1:
The patent specifies a narrow tip angle of at most 5 degrees, which is a relatively broad parameter range compared to more precise angular specifications. This parameter choice enables effective small volume handling while maintaining reasonable manufacturing feasibility, balancing measurement precision for small volumes with practical manufacturing precision requirements.
4Speed
If the plunger is retracted to create a post-sample airgap, then liquid velocity increases for non-contact dispensing, but dead volume increases
Solution Approach 1:
The narrow tip angle of at most 5 degrees modifies the fluid dynamics within the tip, allowing for more efficient liquid ejection. This geometric parameter change reduces the dead volume that would otherwise remain after plunger retraction, enabling better utilization of the aspirated liquid while still achieving the necessary velocity for non-contact dispensing.
5Loss of substance
If the plunger is retracted to create a pre-sample airgap, then all liquid can be dispensed without dead volume, but the device complexity increases
Solution Approach 1:
The narrow tip angle geometry of at most 5 degrees creates favorable surface tension and adhesion characteristics that allow the liquid to form a continuous column. This geometric parameter modification enables complete liquid dispensing without requiring complex pre-sample airgap mechanisms, thus reducing device complexity while eliminating dead volume.
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 narrow angle pipette tip ensures uniform liquid attachment, allows for efficient handling of very low volumes, reduces dead volume, and provides a large dynamic range, enabling precise and efficient aspiration and dispensing of liquids from 0.1 μl to 100 μl, suitable for various sample volumes.
Implementation Method 1
the geometry of a known pipette tip, which has a much wider pipette tip angle than the pipette of the first aspect, is such that the liquid would attach to one side of the inner wall surface of the pipette tip and/or plunger due to surface tension
Data Source
AI summary
There is provided a pipette for aspirating and/or dispensing liquids, comprising a pipette tip and a plunger. The pipette tip has a proximal end and a distal end defining a longitudinal axis therebetween; an aperture at the distal end, and a fluid cavity extending from the aperture at least partially towards the proximal end. The plunger is positioned inside the pipette tip, and extends at least partly between the proximal and distal ends of the pipette tip into the end portion, and is movable towards and away from the aperture to aspirate or dispense fluid from the pipette tip. The pipette tip has an end portion disposed at the distal end, having an inner wall surface extending at an angle of between 2 degrees and 5 degrees relative to the longitudinal axis, for at least 5 mm.