An automated system for high-throughput generation and optimization of microdroplets

Abstract

Microdroplets have been widely used in various biomedical applications. During droplet generation, parameters are manually adjusted to achieve the desired size of droplets. This process is tedious and time-consuming. In this paper, we present a fully automated system for controlling the size of droplets to optimize droplet generation parameters in a microfluidic flow-focusing device. The developed system employed a novel image processing program to measure the diameter of droplets from recorded video clips and correspondingly adjust the flow rates of syringe pumps to obtain the required diameter of droplets. The system was tested to generate phosphate-buffered saline and 8% polyethylene (glycol) diacrylate prepolymer droplets and regulate its diameters at various flow rates. Experimental results demonstrated that the difference between droplet diameters from the image processing and manual measurement is not statistically significant and the results are consistent over five repetitions. Taking the advantages of the accurate image processing method, the size of the droplets can be optimized in a precise and robust manner via automatically adjusting flow rates by the feedback control. The system was used to acquire quantitative data to examine the effects of viscosity and flow rates. Droplet-based experiments can be greatly facilitated by the automatic droplet generation and optimization system. Moreover, the system is able to provide quantitative data for the modelling and application of droplets with various conditions in a high-throughput way. Published by AIP Publishing.

Rapid and Inexpensive Fabrication of Multi-Depth Microfluidic Device using High-Resolution LCD Stereolithographic 3D Printing

“…The mineral oil (light, high purity, VWR International, Radnor, PA, USA) with 20% v/v Span 80 surfactant (Sigma-Aldrich, St. Louis, MO, USA) was used as the oil phase. The experimental setup was the same as in a previously reported article [26]. Briefly, two syringe pumps (Kent Scientific, Torrington, CT, USA) were used to infuse the water and oil phases at the flow rates of 2 µL/min and 5, 10, 20, or 40 µL/min, respectively.…”

“…The channel is visualized by the yellow food dye ( Figure 7B) in which no leakage was observed. Experimental setup established in our previous study [26] was utilized in the droplet generation experiment ( Figure 7C). The flow rate of the water phase was fixed at 2 µL/min, whereas the flow rate of the oil phase was changed to regulate the size of droplets.…”

dDrop-Chip: disposable film-chip microfluidic device for real-time droplet feedback control

“…19 Previously, closed-loop feedback control methods in image-processing have been used to obtain monodisperse droplets, because of their practicality and simplicity. 18,[20][21][22] Although imageprocessing methods 23,24 are suitable for the post-analysis of droplet formation, they cannot be used to control droplets in real time. Their performance is also determined by the quality of the optical units, such as lenses, cameras, and microscopes.…”

Joule heating-induced particle manipulation on a microfluidic chip

“…Recently, a new technique, known as rapid electrokinetic patterning (REP) have emerged as an alternative method for concentration, patterning and sorting of colloidal particles. [25][26][27][28] REP utilizes a highly focused laser beam on the parallel-plate electrodes to generate localized hot-spot.…”

“…Using REP it is also possible to enhance the sensitivity of detection of a bead-based bioassay system. 25,26 Combined effects of electrothermal flow with insulator-based dielectrophoresis can also trap micrometer and submicrometer particles efficiently. 31,32 For such a scenario, insulating structures generates Joule heating leading to electrothermal flow, which entrains colloidal particles to enrich at the vicinity of insulating tips.…”