Microfluidic Lipid Nanoparticle Mixing for Uniform Size Control
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Solution Overview
Problem
Existing methods struggle to control the size and composition of lipid nanoparticles for nucleic acid delivery due to spontaneous aggregation of phospholipids and cholesterol, leading to non-uniform particle formation and inefficient encapsulation of nucleic acids.
Innovation Solution
A microfluidic device with multiple inlet channels, a mixing channel containing microposts, and an outlet channel is used to control the molar ratios of lipid components and Reynolds number, enabling precise regulation of nanoparticle size and composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cholesterol is included in lipid nanoparticles to improve drug loading efficiency and particle stability, then these properties are improved, but uniformity of nanoparticle size and composition becomes difficult to achieve
Solution Approach 1:
The patent applies parameter changes by precisely controlling the molar ratio of cholesterol to phospholipids and regulating the Reynolds number of the fluid flow. By adjusting these parameters within specific ranges (cholesterol:phospholipid molar ratio of 0.1-1.0, Reynolds number of 10-150), the system achieves both high particle stability and uniform nanoparticle size distribution, resolving the contradiction between reliability and manufacturing precision.
Solution Approach 2:
The patent replaces conventional mechanical mixing methods with a microfluidic system that utilizes controlled laminar flow and Dean vortices generated by curved channels. This substitution enables more uniform mixing of cholesterol and phospholipids at the molecular level, achieving consistent nanoparticle formation without the aggregation problems that occur with traditional mechanical mixing.
2Ease of manufacture
If conventional mixing methods are used to synthesize lipid nanoparticles, then the process is simple, but nanoparticles of different sizes such as micelles and liposomes are formed due to spontaneous aggregation
Solution Approach 1:
The patent replaces simple mechanical mixing with a sophisticated microfluidic system that utilizes controlled laminar flow, Dean vortices in curved channels, and focused ultrasonic waves. This substitution maintains ease of operation through automated fluid control while achieving precise nanoparticle size control by preventing spontaneous aggregation through controlled mixing conditions and rapid encapsulation.
Solution Approach 2:
The patent incorporates periodic focused ultrasonic waves as a disturbance to enhance mixing and prevent aggregation. The periodic nature of ultrasonic waves creates cyclic flow patterns that continuously renew the mixing process, ensuring uniform distribution of lipid components and consistent nanoparticle size throughout the synthesis process.
3Adaptability or versatility
If equimolar ratio of phospholipids to cholesterol is used for long sequence nucleic acids like mRNA, then the nucleic acids can be encapsulated, but the cholesterol content becomes excessively high leading to poor encapsulation for short sequence nucleic acids
Solution Approach 1:
The patent applies dynamics by making the cholesterol to phospholipid molar ratio adjustable rather than fixed. The system can dynamically adapt the composition ratio based on the specific application requirements - using lower cholesterol ratios (0.1-0.5) for long sequence nucleic acids like mRNA to avoid excessive cholesterol content, and higher ratios (0.5-1.0) for short sequence nucleic acids to improve encapsulation efficiency. This dynamic adjustment capability enables versatile performance across different nucleic acid types.
Solution Approach 2:
The patent utilizes parameter changes by precisely controlling the molar ratio of cholesterol to phospholipids within the range of 0.1 to 1.0, and by regulating the Reynolds number within 10 to 150. These parameter adjustments enable optimal encapsulation conditions for both long and short sequence nucleic acids, achieving high encapsulation efficiency across different applications while maintaining manufacturing precision through controlled synthesis conditions.
4Reliability
If high cholesterol content is used to improve particle stability, then particle stability is improved, but the fluidity of the biomembrane decreases and binding between phospholipids becomes stronger
Solution Approach 1:
The patent applies parameter changes by precisely controlling the cholesterol to phospholipid molar ratio within the optimal range of 0.1 to 1.0. This controlled ratio adjustment allows the system to achieve sufficient particle stability through adequate cholesterol content while maintaining appropriate biomembrane fluidity and phospholipid binding characteristics. The microfluidic process ensures consistent composition throughout the nanoparticle population, resolving the contradiction between stability and compositional stability.
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 method achieves lipid nanoparticles with a polydispersity index of 0.3 or less, nucleic acid encapsulation efficiency of 50% or more, and loading efficiency of 15% or more, enhancing therapeutic efficiency by encapsulating messenger RNA and oligonucleotides at high concentrations.
Implementation Method 1
the curved channel generates Dean vortices to mix the lipid mixture and the nucleic acid
Implementation Method 2
the microfluidic device utilizes laminar flow and Dean vortices
Implementation Method 3
followed by treatment with ultrasonic waves to disrupt and resuspend aggregates
Implementation Method 4
adjusting the Reynolds number... the curved channel generates Dean vortices... Reynolds number of 10 to 150
Data Source
AI summary
The present invention relates to a microfluidic device for preparing lipid nanoparticles capable of delivering nucleic acids, and a method for preparing lipid nanoparticles using the same. Using the microfluidic device, lipid nanoparticles having a desired size can be prepared by adjusting the molar ratio of compositions and the Reynolds number.