Syringe-pump-induced fluctuation in all-aqueous microfluidic system implications for flow rate accuracy

Abstract

We report a new method to display the minute fluctuations induced by syringe pumps on microfluidic flows by using a liquid-liquid system with an ultralow interfacial tension. We demonstrate that the stepper motor inside the pump is a source of fluctuations in microfluidic flows by comparing the frequencies of the ripples observed at the interface to that of the pulsation of the stepper motor. We also quantify the fluctuations induced at different flow rates, using syringes of different diameters, and using different syringe pumps with different advancing distances per step. Our work provides a way to predict the frequency of the fluctuation that the driving syringe pump induces on a microfluidic system and suggests that syringe pumps can be a source of fluctuations in microfluidic flows, thus contributing to the polydispersity of the resulting droplets.

Decorrelation correction for nanoparticle tracking analysis of dilute polydisperse suspensions in bulk flow

“…To reduce instrument broadening [39], particle trajectories spanned many time steps, and to reduce distribution fitting error, numerous particle tracks were simulated. Simulations applied a constant, uniform bulk fluid flow; however, experiments were performed with no applied bulk flow because syringe pump jitter can introduce dynamic drift [40]. A 'true' measurement for % error of PSD parameters was obtained without any drift correction.…”

All-aqueous multiphase microfluidics

“…Consequently, the two phases are usually separated by a long and straight interface. This water/water interface is sensitive to the vibrations 28,79 in the surrounding environment as long as the viscosities are not exceedingly large. To take advantage of this property, mechanical perturbations have been introduced to oscillate the jet phase, inducing breakup of the jet, 28,29 as shown in Figures 1(a)-1(c).…”

Determination of aqueous two phase system binodal curves using a microfluidic device

“…These steps create small variations of the volumes of the solutions being inserted in the microchannel [15]. Although these volume fluctuations are small, nevertheless they create small variations in the concentrations of PEG and phosphate in the microchannel and, when the system is very close to the binodal curve, they can cause the system to oscillate between the states in which the system can either separate or not in two phases.…”