MicroFluidic Pumping System
Introduction: MicroFluidic Pumping System
The Challenge
Investigating biological processes often requires model systems that mimic naturally occurring physiological environments. Many animal models and cell lines have served as gold standard tools for biomedical researchers to investigate biological functions in laboratories. Yet, many vital bio-activities such as hormones production rely on fluid dynamics to propagate signalling molecules at the right place and time throughout the body. In investigating such long-range communication mechanisms, a need exist to precisely mimic and control physiological fluid environments in laboratory settings. As a result, many commercial pumping systems are now available:
* Programmable syringe pump system *
* Peristaltic Pumping system *
* Pressure controller system **
Yet, commercial solutions come highly expensive and are difficult to customize based on application requirements. As a result, various low-cost open source solutions have recently emerged in the literature:
* Open-source syringe pump system **
* Pressure controller *
* Piezoelectric pumping system *
Although being low cost and easily customizable, open-source solutions lack an intuitive user interface allowing to easily adjust pumping parameters without modifying the underlying source code of the system.
Project Objectives / Scope
The present project aims to improve the design of the PiFlow system by designing a graphical user interface to be displayed on an LCD touch screen display to adjust flow rate parameters easily. Specifically, the interface will allow the user to select between three different modes. The static flow mode will allow setting a constant flow rate (uL/Min) to be executed for a pre-defined flow time (Sec). 171
The dynamic flow mode will allow the user to select a range of flow rate values where the system will linearly adjust the pumping rate (uL/Min) following a pre-defined sweep rate (uL/Min) adjustable through the interface. Lastly, for applications requiring higher complexity, a custom mode will allow the upload of a CSV file containing a list of flow rate parameters to be executed by the system. The underlying code of the interface will be made available for modification and improvement on the Github Project Page. Overall, the interface serves as a first design iteration utilizable in various microfluidic open source systems.
Supplies
Mechanical Components
* 3D Printing Filament - PLA Plastic
* 3D Printer - Creality Ender 3
* Clear Plastic Glue
Electronic Components
* 1x Raspberry Pi 3 Model B
* 2x High Pump Driver (Best for high flow rate application - Select the driver according to required flow rate)
* 2x Low Pump Driver (Best for low flow rate application - Select the driver according to required flow rate)
* 2x 0.1 uF Decoupling Capacitor
* 2x TMU Switch IC
* 2x Molex Connector
* Raspberry Pi Pin Connectors
* 1x 7'' LCD Screen
* 1x HDMI 90' Adapter
* 1x HDMI Extender Capble
Fluidic Components
* Tygon tubing 1.3 mm inner diameter
* 2x Piezoelectric Pump
* Luer Tubing Adapter
Software & Manufacturing House
* Autodesk Eagle
* JLC PCB
* Fusion 360
* The Eric Python IDE
* QT Designer
Step 1: Mechanical Design
Procedures
* Fusion 360 was utilized to design the components. The STL files provided below can be downloaded and uploaded directly into a 3D printer. Alternatively, the Fusion 360 Model can be downloaded from the Autodesk Gallery.
* The printing parameters selected according to standard recommendations for PLA material:
Bed Temperature --> 70C
Nozzle Temperature --> 220C
Flow Rate --> 90%
* Each component was assembled using Clear Plastic Glue which was found to be durable. Alternatively, the design can be modified to allow assembly with screws.
* Holes were drilled according to the Luer Tubing Adapter dimensions. Clear plastic glue was used to mount the adapters.
* The inner diameters of the bottle holders can be adjusted according to the size of the solution vessels utilized.
Step 2: Electronic Circuit
Electronic Components
* 1x Raspberry Pi 3 Model B
* 2x High Pump Driver (Best for high flow rate application - Select the driver according to required flow rate)
* 2x Low Pump Driver (Best for low flow rate application - Select the driver according to required flow rate)
* 2x Piezoelectric Pump
* 2x 0.1 uF Decoupling Capacitor
* 2x TMU Switch IC
* 2x Molex Connector
* Raspberry Pi Pin Connectors
* 1x 7'' LCD Screen
* 1x HDMI 90' Adapter
* 1x HDMI Extender Cable
Design Software & Manufacturing House
* Autodesk Eagle
* JLC PCB
* Fusion 360
Procedures
* Upload each component into Eagle software. 737