Micro-pipe Droplet Generation via Vibration
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Solution Overview
Problem
Current methods for generating microdroplets lack precision and control over volume, making them unsuitable for complex biochemical reactions and analyses, particularly in microreactors and digital single molecule/cell analysis, where precise control of droplet size and quantity is crucial.
Innovation Solution
A droplet generating method using a micro-pipe with a liquid driving device and vibrating equipment to create relative periodic vibrations, allowing the micro-pipe outlet to touch a second liquid, overcoming surface tension and adhesion forces to produce uniform droplets with controlled sizes and volumes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional methods (emulsion polymerization, membrane emulsification, spay emulsification) are used to generate microdroplets, then microdroplets can be produced for microsphere and drug carrier preparation, but the volumes of the microdroplets cannot be precisely and accurately controlled
Solution Approach 1:
The patent replaces conventional mechanical emulsification methods with a microfluidic system that uses controlled fluid flow through microchannels to generate microdroplets. The precise control of droplet volume is achieved by regulating the flow rates of dispersed and continuous phases through the microchannel structure, eliminating the volume control limitations of traditional mechanical methods.
Solution Approach 2:
The patent changes the physical parameters of the system by using immiscible liquids with specific interfacial tension properties and controlling their flow rates through microchannels. By adjusting the flow rate ratio between dispersed and continuous phases, and modifying microchannel dimensions, the system achieves precise control over microdroplet volume while maintaining high productivity.
2Manufacturing precision
If microfluidic channels are used to generate uniform microdroplets, then droplet uniformity can be improved, but the volumes of the microdroplets are limited by the structure of the microchannel and surface feature modification
Solution Approach 1:
The patent designs a versatile microfluidic system where a single microchannel structure can generate microdroplets across a wide volume range by adjusting operational parameters (flow rates, phase ratios) rather than requiring different channel structures for different volumes. This multi-functionality allows the system to maintain droplet uniformity while adapting to various volume requirements.
Solution Approach 2:
The patent introduces dynamic control of flow rates and phase ratios to enable the microfluidic system to adaptively generate microdroplets of different volumes. By dynamically adjusting the flow parameters during operation, the system overcomes the static volume limitations imposed by fixed microchannel structures and surface modifications.
3Manufacturing precision
If microdroplets are generated in microchannels, then uniform droplets can be produced, but the microdroplets must be transferred to a storage container by specific device and method, which increases difficulty to locate, extract, and analyze the microdroplets
Solution Approach 1:
The patent extracts microdroplets directly from the microchannel flow into a collection container through controlled disruption of the continuous phase flow. This extraction method allows uniform droplets to be generated in the microchannel while simplifying their transfer and storage by eliminating the need for complex transfer devices and methods.
4Productivity
If capillary methods are used to eject or spray liquid into microwell, then microdroplets can be generated, but it is difficult to precisely control quantity of microdroplets due to surface tension and adhesion force
Solution Approach 1:
The patent replaces capillary-based mechanical ejection methods with a microfluidic system that uses controlled fluid dynamics and interfacial tension management. By regulating the flow rates of immiscible phases through microchannels, the system achieves precise control over microdroplet quantity and volume, overcoming the uncontrollable surface tension and adhesion forces that plague capillary methods.
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 precise and efficient generation of multitudinous droplets with controllable sizes and volumes, enhancing the precision and efficiency of microreactions and analyses, and simplifying the handling and storage of microdroplets.
Implementation Method 1
forming a relative periodic vibration between the micro-pipe and the container so that the outlet end of the micro-pipe is displaced to touch the second liquid in the container during a relative periodic vibration
Implementation Method 2
providing a liquid driving device connecting to the micro-pipe through a connecting tube for driving the first liquid through the micro-pipe and out from an outlet end of the micro-pipe
Implementation Method 3
it is difficult to precisely control quantity of microdroplets due to a surface tension between the liquids inside and outside the capillary, and an adhesion force between the microdroplet and an orifice of the capillary
Data Source
AI summary
A droplet generating method includes the steps of providing a micro-pipe having an outlet end; providing a liquid driving device to generate a flow of a first liquid; locating and positioning the micro-pipe which extends along a vertical longitudinal axis; connecting the liquid driving device with the micro-pipe so that the first liquid flows and is emitted out from the outlet end; providing a container, which is positioned at least in-part below the micro-pipe and adapted to contain a second liquid including a liquid surface disposed at a position located between a highest and a lowest positions; and either vertically or horizontally vibrating the micro-pipe, and thereby forming a plurality of droplets of the first liquid emitted from the outlet end at a position below the liquid surface of the second liquid.