Microfluidic Collection Region Velocity Gradient for Cell Concentration
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Solution Overview
Problem
Microfluidic devices face challenges in accommodating small numbers of cells for analysis, particularly in seeding cells and achieving sufficient cell density for downstream culture or assays, due to limitations in macroscale prep methods like centrifugation, which are complex and costly.
Innovation Solution
A microfluidic device design with an input channel, output channel, and collection region, where the sample fluid flows at different velocities to concentrate particles in the collection region, utilizing a pressure gradient generated by reservoir and pumping drops to facilitate cell collection and concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If basic centrifugation is used for pre-concentration, then cell density is increased, but the method has a practical limit when cell numbers are extremely small (less than 50,000 target cells)
Solution Approach 1:
The patent replaces the mechanical centrifugation system with a microfluidic device that uses controlled fluid flow and pressure gradients to achieve particle concentration. This substitution allows for gentler handling of rare cells while maintaining concentration efficiency, overcoming the limitation of centrifugation for samples with less than 50,000 target cells.
Solution Approach 2:
The patent changes the physical parameters of the fluid system by controlling flow velocity and pressure gradients within the microfluidic device. By adjusting these parameters, the device can adapt to different cell concentrations and sample volumes, making it versatile for both common and rare cell types including those with extremely low abundances.
2Measurement precision
If microfluidic devices are used to increase cell:volume ratios, then sensitivity for autocrine and paracrine cell signaling is improved, but the devices face challenges in accommodating small numbers of cells for analysis
Solution Approach 1:
The patent implements preliminary concentration of particles within the microfluidic device itself, eliminating the need for separate pre-concentration steps. The device includes a concentration region that pre-concentrates particles from the input flow before they reach the culture region, making the system easier to operate with small cell numbers while maintaining high cell:volume ratios for sensitive signaling detection.
Solution Approach 2:
The microfluidic device performs multiple functions within a single integrated system: it concentrates particles, maintains high cell:volume ratios for sensitive signaling, and provides controlled fluid flow. This multi-functionality resolves the contradiction by making the device both sensitive for signaling detection and easy to operate with various cell numbers.
3Reliability
If macroscale techniques are used for cell analysis, then robust readout can be achieved, but it is difficult to perform replicates with small cell numbers from liquid biopsies
Solution Approach 1:
The patent segments the microfluidic device into distinct functional regions: an input channel, a concentration region, and a culture/analysis region. This segmentation allows the device to efficiently concentrate rare cells from large volumes while maintaining enough cells for multiple replicates, thereby improving productivity without sacrificing readout reliability.
Solution Approach 2:
The patent uses parameter changes in fluid flow velocity and pressure gradients to optimize particle concentration efficiency. By carefully controlling these parameters, the device can concentrate sufficient numbers of rare cells to enable multiple replicates while maintaining the sensitivity needed for reliable readout, thus resolving the contradiction between robustness and productivity.
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 and cost-effective concentration of particles from dilute samples, allowing for gentle treatment and processing of small cell numbers, enhancing the functionality of microfluidic devices in handling rare cell types and samples.
Implementation Method 1
The sample fluid is flowed through the input channel and the output channel at a first velocity and through the collection region at a second velocity less than the first velocity such that the particles collect in therein
Implementation Method 2
utilizing a pressure gradient generated by reservoir and pumping drops to facilitate cell collection and concentration
Data Source
AI summary
A method is provided for collecting a concentration of particles from a sample fluid containing the particles. The method includes the steps of providing a microfluidic device. The microfluidic device includes an input channel, an output channel and a collection region. The input channel has an input end and an output end. The output channel has an input end and an output end. The collection region interconnects the output end of the input channel and the input end of the output channel. The sample fluid flows through the input channel and the output channel at a first velocity and through the collection region at a second velocity less than the first velocity such that the particles collect in therein.