Ordered-Stream Microfluidic Co-Encapsulation for Cell Interaction Screening
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Solution Overview
Problem
Current high-throughput cell screening methods focus on encapsulating single cells in droplets, failing to capture valuable cell-cell interaction data.
Innovation Solution
A method for generating single droplets containing one cell from a first ordered stream and at least one cell from a second ordered stream, utilizing inertial focusing and controlled fluid flow to achieve high-throughput and efficient co-encapsulation, exceeding Poisson distribution predictions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If flow velocity is increased to enhance inertial focusing of cells, then cell ordering efficiency is improved, but droplet generation fails due to jetting or co-flow regimes
Solution Approach 1:
The system dynamically adjusts flow rates of aqueous and oil phases to maintain optimal conditions for both cell ordering and droplet generation. The flow rates are tuned so that the aqueous phase flows fast enough to inertially focus cells into ordered streams, but slow enough to allow proper droplet formation at the junction, preventing jetting or co-flow regimes
Solution Approach 2:
The invention changes multiple parameters simultaneously including flow velocity, channel dimensions, and cell concentration to achieve the desired balance. By adjusting these parameters, the system maintains the aqueous flow velocity within a specific range that enables both effective cell ordering through inertial focusing and reliable droplet generation without jetting
2Reliability
If flow velocity is decreased to enable droplet generation, then droplet formation is achieved, but cell inertial focusing becomes insufficient
Solution Approach 1:
The system uses dynamic flow rate control to ensure that the aqueous phase maintains sufficient velocity for cell ordering while still enabling droplet generation. The oil phase flow rate is adjusted relative to the aqueous phase to compensate for the reduced velocity, ensuring that droplets form at the correct location and contain the properly ordered cells
Solution Approach 2:
The oil phase acts as an intermediary that facilitates droplet generation while the aqueous phase maintains cell ordering. By carefully controlling the ratio and flow rates of these two phases, the system achieves both cell ordering and droplet formation even when the aqueous phase velocity is reduced
3Measurement precision
If single cells are encapsulated in single droplets, then single-cell data extraction is achieved, but cell-cell interaction data is lost
Solution Approach 1:
The system performs preliminary ordering of cells in streams before encapsulation, arranging cells in a controlled sequence. This preliminary action enables the subsequent encapsulation of multiple cells from different streams in the same droplet while maintaining the ability to trace which cells interacted, thus preserving cell-cell interaction data without sacrificing single-cell resolution
Solution Approach 2:
The invention merges multiple ordered streams of cells into single droplets containing multiple cells. By maintaining the ordered structure from separate streams and combining them in controlled co-encapsulation, the system enables both single-cell tracking and observation of cell-cell interactions within the same droplet
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 the generation of droplets with a higher fraction of desired cell pairs at increased rates, facilitating high-throughput cell-cell interaction assays with improved data capture.
Implementation Method 1
cells in an ordered stream are lined up in a single file through a process known as inertial focusing caused by Dean forces. Inertial focusing pushes cells in a tangential direction to the direction of flow, until cells reach an equilibrium position
Implementation Method 2
inertial focusing caused by Dean forces
Implementation Method 3
the droplet is generated when the aqueous streams meet with the oil-phase sheath fluid at a junction of the microfluidic device... generating the single droplet formed from the first aqueous phase, the second aqueous phase, and the oil phase
Data Source
AI summary
Disclosed are methods and microfluidic devices for successfully co-encapsulating two or more cells in a high-throughput, high efficiency manner. Cells are organized into two or more ordered streams flowing through separate microchannels of the microfluidic device. Cells in ordered streams are sufficiently spaced such that at a junction of the microfluidic device, single droplets are generated that include exactly one cell from the first ordered stream of cells and at least one cell from the second ordered stream of cells. Single droplets including two or more cells are useful for performing assays (e.g., high throughput cell-cell interaction assays).