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Cellix Technical Team

Droplet generation of water-in-oil droplets using Cellix's 4U Pump: a step-by-step process

Introduction

4U 4-channel microfluidic pump is a precision pressure pump for a variety of microfluidic applications, where accurate and stable flow rate delivery is required. You can control all the features of the pump with the SmartFlo program running on a PC.


Key Benefits of the 4U Pump:

  • FAST RESPONSE and fast settling time.

  • PULSE-FREE down to uL/min with flow sensor.

  • PROGRAMMABLE flow profiles with any combination of constant, ramp, sine and step.

  • EASY INTEGRATION with your own software - LabVIEW, C++, Python, etc.

  • FLOW RATES: 1uL/min - 1mL/min.

  • INPUT PRESSURE: up to 10 bar or 145 PSI - external compressor or vacuum pump required.

  • CLOSED-LOOP FEEDBACK: Flow sensors provide active feedback and precise flow control.

  • EASY TO USE: simple software control via SmartFlo program for your PC.


In this blog, we will walk you through the setup and demonstration of Cellix's 4U Pump for a specific microfluidic application: droplet generation of water-in-oil droplets. This application showcases the pump's capabilities in creating uniform and stable droplets, essential in various scientific and research endeavors.


Understanding the setup:

  • To do this, connect the power leads to the 4U Pump and to the Compressor.

  • Connect the compressor to the 4U pump via the red pneumatic tubing.

  • Connect the 4U pump to the 15mL Sample Reservoir via the blue pneumatic tubing.

  • Pipette 1mL of DropGen oil into a 15mL Sample tube and label this sample tube as the “oil” phase. Then place the Oil sample into the Sample Reservoir holder.

  • Similarly, pipette the aqueous phase into a 15mL Sample tube and label it – in this example, we label it as H20.

  • To connect the Oil sample to the microfluidic chip;

    • First, connect the blue PEEK tubing to the Oil sample tube

    • Connect the 80uL Flow Sensor to the 4U Pump Channel 1.

    • Then connect the tubing from the Oil sample tube to the input of the 80uL Flow Sensor.

    • Finally, connect the blue PEEK tubing to the outlet of the 80uL Flow Sensor

  • To connect the Aqueous phase (H20 in this set-up) to the microfluidic chip:

    • First, connect the blue tubing to the H20 Sample tube.

    • Connect the 7uL Flow Sensor to the 4U Pump Channel 2.

    • Then connect the tubing from the H20 Sample tube to the input of the 7uL Flow Sensor.

    • Finally, connect the red PEEK tubing to the outlet of the 7uL Flow Sensor.

  • Now place the DropChip into the DropChip Frame. Place the top of the frame over the chip but do not clamp the thumbscrews yet. The DropChip has one Flow Splitter & 3 Droplet Generators. There are two different designs of the Droplet Generator. In this demonstration, we are using the Flow Splitter and the 1st Droplet Generator on the DropChip. The droplet generator has been pre-coated with Cellix’s DropGen PreCoat solution to ensure hydrophobicity for the creation of uniform, stable, water-in-oil droplets


  • To connect the oil phase to the flow splitter on the DropChip:

    • First, start the flow rate of the Oil Phase (Channel 1 of the 4U pump) at 50uL/min.

    • This primes the blue PEEK tubing from the Oil Sample tube.

    • Once you see droplets emerging at the output of the blue tubing from the 80uL Flow Sensor, connect to the input of the Flow Splitter on the DropChip.

    • Now connect the 2x short blue PEEK tubings from the output of the Flow Splitter.

    • Once you see droplets emerging at the outputs of the 2x short blue PEEK tubings, connect to the input of the droplet generator on the DropChip.

    • The oil is now flowing and priming the Droplet Generator.



  • To connect the aqueous phase (H20 in this set-up) to the Droplet Generator on the DropChip:

    • First, start the flow rate of the Aqueous Phase (Channel 2 of the 4U pump) at 5uL/min. This primes the red PEEK tubing from the Aqueous/H20 Sample tube.

    • Once you see droplets emerging at the output of the red tubing from the 7uL Flow Sensor, connect to the input of the Droplet Generator on the DropChip.


Finally, to collect the droplets, place the Eppendorf in the Eppendorf holder on the microscope stage. Connect the Tygon tubing via a stainless steel pin to the output of the Droplet Generator and place in the Eppendorf.


And that’s it, you’ve just completed your first droplet generation assay with Cellix’s 4U Pump and DropChip. If you’d like to learn more about our Microfluidic Solutions, then check out our eShop or get in contact with us now.










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