I am using an MFFD to create hyaluronic acid microgels. While I have been able to get stable flow over the course of 4 hours, I seem to get alternating flow patterns which generate either many small droplets or one large droplet. Is this a consequence of using a syringe pump?
I have attached a sped up video to demonstrate this.
Continuous phase: Light mineral oil, span 80
Dispersed phase: Norbornene-Hyaluronic acid in PBS, DTT, I2959
Pump: Chemyx fusion 6000
Flow rates: 1ul/min for dispersed and 1.9ul/min for continuous
Thank you!
I believe it is because of pressure instability.
1) For low flow rates such as the ones you have used - try using small diameter syringes. This creates enough piston travel distance per rotation of the axle of your pump.
2) Try initiating the flow with just the continuous phase. Once the flow is stable, then initiate the dispersed phase.
3) In any case, displacement pumps do have a degree of pulsation. You might want to consider continuous pumping options - such as pressure-driven pumps or a HPLC pump that can create a more stable flow.
Thank you for your recommendations Anand Narayanan Pallipurath Radhakrishnan Tan Zheng Lin Zebing Mao
I will switch to a smaller diameter syringe for the continuous phase and see if that helps!
Anand Narayanan Pallipurath Radhakrishnan changing to a smaller syringe for my continuous phase solved it! Thanks! And just to mention I am using 2 hamilton 1mL gastight syringes. :)
Kassondra Hickey : That is great news! Good luck with your experiments and happy to help!
Hi,
As Anand said it is due to the pressure/flow rate fluctuations. Due to the mechanism of the stepper motor inside syringe pump there is always oscillation in flow rate. Using smaller syringe may help. But the best thing that you can do to get rid of the fluctuations is compliance effect. If you use flexible tubing it can damp fluctuations.
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