Laser Optical Pressure Microfluidic Particle Separation
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Solution Overview
Problem
Current methods for separating particles in fluids based on size and refractive index are limited in their ability to effectively differentiate and separate chemically distinct particles, particularly in biological samples, due to reliance on size-dependent optical pressure techniques.
Innovation Solution
The use of optical pressure generated by a collimated light source to separate particles of varying refractive indices and sizes by manipulating the laser beam focus and position within a microfluidic device, allowing for the separation and analysis of chemically distinct particles based on their refractive indices and physical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If size-based optical pressure separation is used, then particles can be separated by size, but the ability to differentiate and separate chemically distinct particles is limited
Solution Approach 1:
The patent changes the separation parameter from size-based to refractive index-based by adjusting the optical pressure conditions. By controlling laser power, flow rate, and channel geometry, particles are separated based on their refractive index values rather than size, enabling differentiation of chemically distinct particles with similar sizes
Solution Approach 2:
The patent replaces traditional mechanical or gravitational separation methods with optical pressure-based separation. By using laser-induced optical pressure in a microfluidic channel, the system achieves separation based on optical properties (refractive index) rather than mechanical properties, improving chemical differentiation capability
2Force
If laser focus is intensified to increase optical pressure, then separation force increases, but beam divergence increases making focus maintenance difficult
Solution Approach 1:
The patent implements dynamic control of the laser beam through motorized translation stages that can adjust the beam position and focus in real-time. This dynamic adjustment system allows the operator to maintain optimal focus and intensity levels while compensating for beam divergence, keeping the high optical pressure force sustained along the channel
Solution Approach 2:
The patent introduces optical elements (lenses, mirrors) and translation stages as intermediaries between the laser source and the fluid channel. These intermediaries enable precise control and maintenance of beam focus, allowing intense optical pressure to be applied without direct manual adjustment of the laser itself
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 efficient separation and identification of particles by their refractive index, allowing for the concentration of specific entities in a mixture and providing insights into biological samples, such as disease states, through the deformation of particles against a glass wall under optical pressure.
Implementation Method 1
the particles are subjected to optical pressure near the beam focal point (i.e., the region of highest photon density) intense enough to impart momentum sufficient to overcome fluid drag forces
Implementation Method 2
a collimated light source operable to generate a collimated light source beam
Implementation Method 3
the particles remain stationary when the optical pressure equals the force exerted on the particles by the liquid flow (i.e., Stoke's force)
Implementation Method 4
the region of highest photon density intense enough to impart momentum
Implementation Method 5
the force due to optical pressure of the laser, Foptical—pressure, is given by equation 1
Implementation Method 6
Q* defines the conversion efficiency of optical pressure transfer arising from light reflection and refraction based upon geometrical considerations
Implementation Method 7
a pump in communication with the fluid input reservoir and operable to deliver the fluid through the microfluidic device at a controlled flow rate
Implementation Method 8
a collimated light source operable to generate a collimated light source beam, the collimated light source beam comprising a beam cross-section
Data Source
AI summary
A method of particle separation, wherein a collimated light source operable to generate a collimated light source beam is provided. The collimated light source beam includes a beam cross-section. A body is provided, wherein the body defines a wall and a first channel in a first plane. The first channel includes a first channel cross-section, the first channel being oriented to receive the collimated light source beam such that the beam cross-section completely overlaps the channel cross-section. The collimated light source beam is transmitted through the channel. A fluid sample is transmitted through the channel, fluid sample including a plurality of particles of a same type. All of the particles of the plurality of particles are separated axially along the collimated light source beam. All of the particles of the plurality of particles are retained against the wall in the collimated light source beam.