The Importance of Flow Rates in Microfluidic Applications
Perhaps you are in the cosmetic or food industry, or maybe you are performing research on an exciting new subject related to drug delivery or biological science. In any of these cases, you can perform experimental work with microfluidic devices to achieve functionalities like flowing, mixing, purging and dispensing at high resolution with small volumes (Hiung et al., 2016). In such applications, low flow rates are required, and precision is crucial to ensure quality and safety. In this brief review, you will find some important insights to understand better the role of syringe flow rate for your research or ongoing work with microfluidic devices.
Flow Rate Control
Different flow control systems are available in the market and usually implemented for microfluidic devices such as microfluidic peristaltic pumps, recirculation pumps, and syringe pumps. Also, pressure controller systems are for this purpose. However, some important characteristics should be considered before to make a pump selection.
- Peristaltic and recirculation pumps show a pulse behavior in their flow pattern due to its nature, which makes them unreliable for microfluidic applications (Iverson & Garimella, 2008).
- On the other hand, pressure controlled systems allow high pulse-less performance but are expensive and difficult to operate.
- Syringe pumps are a good option since they are more stable than peristaltic and recirculation pumps, but its use is very straightforward (Lake, Heyde, & Ruder, 2017).
Flow Rate Fundamentals
The working principle of a syringe pump system is very simple: the fluid contained in a syringe is pushed by the piston into the microfluidic channel driven by a stepper motor of linear motion. Thus, the flow rate can be controlled by the syringe size and the speed of the piston. The microfluidic pump flow rate is calculated by the following formula:
where Q is the flow rate, v the speed of the piston and S its section (Elveflow, 2017).
Flow Rate Control with Chemyx Syringe Pumps
Syringe pumps are straightforward equipment. Nevertheless, some issues have been found during its operation at low flow rates (under 0.1 μL per minute). This anomalous operation can compromise the flow stability. The minimal motor movement determines the flow stability. Although smaller syringes can improve the flow stability, this can limit the flow rate range and the liquid quantity for the device operation.
Chemyx has overcome the above mention drawbacks and New advances with syringe pump motors have been achieved to an almost pulse-less flow, the new low flow rate syringe pumps are suitable to operate with flow rates from the order of pL to mL like in the case of the Chemyx Fusion 4000 multi-channel syringe pump (Chemyx, 2017).
Flow rate stability with the pulse-less flow is an important future that can be obtained from Chemyx Fusion 4000 syringe pumps. The outstanding performance of Chemyx syringe pump will help you on your research and ongoing work with microfluidic pumps and devices.
- Chemyx. (2017). Chemyx. Retrieved from https://www.chemyx.com/syringe-pumps/fusion-4000/
- Elveflow. (2017). Syringe pumps and microfluidics. Retrieved from https://www.elveflow.com/microfluidic-tutorials/microfluidic-reviews-and-tutorials/syringe-pumps-and-microfluidics/
- Hiung, Y., Universiti, Y., Hussein, T., Fhong, C., Universiti, S., Hussein, T., & Queen, N. Z. (2016). Customizing a high flow rate syringe pump for injection of fluid to a microfluidic device based on polyimide film, Journal of Engineering and Applied Sciences, 11(6).
- Iverson, B. D., & Garimella, S. V. (2008). Recent advances in microscale pumping technologies: A review and evaluation. Microfluidics and Nanofluidics, 5(2), 145–174. https://doi.org/10.1007/s10404-008-0266-8
- Lake, J. R., Heyde, K. C., & Ruder, W. C. (2017). Low-cost feedback-controlled syringe pressure pumps for microfluidics applications. PLoS ONE, 12(4), 1–12.