Microfluidic Perfusion Valves for Low-Shear Biological Analysis
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Solution Overview
Problem
Existing methods for perfusing biological objects in microfluidic systems using external pumps increase the risk of biological contamination, sample loss, and prevent integrated analysis of secretions, while conventional peristaltic pumps cause backflow and shear in hydrodynamic traps.
Innovation Solution
A microfluidic perfusion system with a pump system comprising valves with deformable membranes, controlled by symmetric pressure gradients, transfers fluid through a hydrodynamic trap to perfuse biological objects while minimizing shear and backflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external pump systems (syringe pumps or peristaltic pumps) are used to circulate culture medium in the microfluidic circuit, then fluid circulation and perfusion of the biological object are achieved, but the risk of biological contamination increases, sample loss occurs, and integrated analysis of secretions is prevented
Solution Approach 1:
The patent merges the pump system with the microfluidic circuit by integrating valves and pumping chambers directly into the chip architecture. The pump system comprises valves with deformable membranes that are part of the microfluidic component itself, eliminating the need for external pump systems and enabling integrated secretion collection and analysis within the closed microfluidic environment.
2Productivity
If a peristaltic pump system is integrated into the microfluidic circuit, then collection of secretions is integrated with the culture system, but backflow occurs at the trapping zone and the trapped organoid is subjected to shear stress
Solution Approach 1:
The patent employs dynamic control of valve membranes through pneumatic actuation to create a peristaltic pumping motion. The valves transition between open and closed states in a coordinated sequence, creating a wave-like propulsion of fluid that moves culture medium through the circuit without generating backflow or excessive shear stress at the trapping zone.
Solution Approach 2:
The patent uses pneumatic pressure as an intermediary to control the valve membranes. By applying controlled pressure gradients through pneumatic actuation, the system achieves precise control over valve opening and closing, enabling gentle fluid propulsion that avoids direct mechanical contact with the trapped biological object and minimizes shear stress.
3Speed
If conventional peristaltic pump actuation is used, then fluid pumping is achieved, but backflow occurs at the trapping zone
Solution Approach 1:
The patent implements periodic actuation of the valve membranes through controlled pneumatic pressure cycles. The valves open and close in a rhythmic sequence, creating periodic fluid propulsion that maintains stable flow conditions. This periodic action prevents backflow by ensuring that valves close before pressure reversals occur, maintaining unidirectional flow through the trapping zone.
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 system effectively perfuses biological objects, reducing contamination and shear risks, enabling integrated secretion collection and analysis within the microfluidic circuit.
Implementation Method 1
Each valve comprising a cavity and a deformable membrane inside the cavity, said membrane being controllable by pneumatic actuation between two extreme states, an open state in which it lets a fluid pass and a closed state in which it blocks the passage of the fluid
Implementation Method 2
the second valve being controlled by a first pressure gradient in the closing direction and the third valve by a second pressure gradient in the opening direction
Data Source
Figure 1~2
Figure 3A~3C
Figure 4A
AI summary
The invention relates to a method for analyzing a biological object (O), implemented within a microfluidic perfusion system, said system comprising a microfluidic component (1) integrating a microfluidic circuit (10), said microfluidic circuit having: - A main channel provided with a hydrodynamic trap (P_H) receiving said biological object (O) to be perfused, - A microfluidic inlet channel (100) connected to the main channel upstream of the hydrodynamic trap (P_H), - A microfluidic outlet channel (101) connected to the main channel downstream of the hydrodynamic trap (P_H), - A first valve (V1) positioned on the microfluidic inlet channel (100), - A pump system formed by a series composed of at least a second valve (V2) and a third valve (V3) positioned on the microfluidic outlet channel (101).