Tone Burst Control for Acoustic Droplet Ejection of Non-Newtonian Fluids
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Solution Overview
Problem
Existing acoustic droplet ejection (ADE) technologies struggle to reproducibly, accurately, and precisely transfer non-Newtonian fluids such as native genomic DNA (gDNA) due to their viscoelastic properties, which cause alignment of polymer chains and hinder droplet breakoff, especially at high concentrations and large fragment sizes.
Innovation Solution
Employing a novel ejection tone burst and increased power regime, typically 6-11 dB above the standard threshold, to compensate for the non-Newtonian nature of the fluid, ensuring droplet breakoff and transfer of intact, native gDNA with sizes over 20 Kb and concentrations over 100 ng/μL.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard acoustic droplet ejection is used for non-Newtonian fluids, then droplet ejection is achieved, but droplet breakoff fails due to polymer chain alignment and viscoelastic stiffening
Solution Approach 1:
The patent changes the acoustic parameters (power level increased by 6-11 dB above standard threshold, modified tone burst duration and frequency) to compensate for the viscoelastic properties of non-Newtonian fluids. This parameter adjustment enables sufficient acoustic energy to overcome the polymer chain alignment resistance and achieve reliable droplet breakoff while maintaining fluid integrity.
2Reliability
If high acoustic power is used to overcome viscoelastic effects, then droplet breakoff is achieved, but fluid integrity may be compromised
Solution Approach 1:
The patent employs dynamic acoustic waveforms with optimized tone burst duration and frequency that adapt to the viscoelastic relaxation times of the fluid. This dynamic approach delivers sufficient peak power for droplet breakoff while controlling the temporal profile to prevent excessive shear forces that would compromise fluid integrity or cause polymer chain damage.
3Productivity
If conventional ADE parameters are used for high concentration gDNA, then transfer speed is maintained, but transfer accuracy decreases due to non-Newtonian behavior
Solution Approach 1:
The patent incorporates feedback mechanisms where the acoustic system monitors and adjusts power levels and waveform parameters based on the observed response of the non-Newtonian fluid. This feedback control enables real-time optimization to maintain both high transfer speed and accurate droplet formation despite variations in fluid concentration and viscoelastic properties.
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
Enables highly reproducible, accurate, and precise transfer of native gDNA without fragmentation, maintaining its integrity and facilitating miniaturized sample handling in laboratory and clinical settings.
Implementation Method 1
an acoustic transducer is positioned beneath the reservoir and focused at the surface of the fluid contained within a well or tube of a microplate. An acoustic wave is generated and propagated through the fluid
Implementation Method 2
The acoustic wave is focused at the surface of the fluid to create an acoustic mound that results in breakoff and ejection of a droplet from the fluid surface
Data Source
AI summary
Methods of ejecting droplets containing a non-Newtonian fluid by an acoustic droplet ejector can include applying a tone burst of focused acoustic energy to a fluid reservoir containing a non-Newtonian fluid at sufficient amplitude to effect droplet ejection according to a tone burst pattern. The tone burst pattern may include three discrete tone burst segments, the first tone burst segment having greater duration than the second and third segments, and third segment having greater duration than the second segment. The exact durations and amplitudes of the tone burst segments can be tuned to influence the ejection properties.