512-Channel Geometric Droplet-Splitting Microfluidic Device by Injection of Premixed Emulsion for Microsphere Production

Abstract

We present a 512-channel geometric droplet-splitting microfluidic device that involves the injection of a premixed emulsion for microsphere production. The presented microfluidic device was fabricated using conventional photolithography and polydimethylsiloxane casting. The fabricated microfluidic device consisted of 512 channels with 256 T-junctions in the last branch. Five hundred and twelve microdroplets with a narrow size distribution were produced from a single liquid droplet. The diameter and size distribution of prepared micro water droplets were 35.29 µm and 8.8% at 10 mL/h, respectively. Moreover, we attempted to prepare biocompatible microspheres for demonstrating the presented approach. The diameter and size distribution of the prepared poly (lactic-co-glycolic acid) microspheres were 6.56 µm and 8.66% at 10 mL/h, respectively. To improve the monodispersity of the microspheres, we designed an additional post array part in the 512-channel geometric droplet-splitting microfluidic device. The monodispersity of the microdroplets prepared with the microfluidic device combined with the post array part exhibited a significant improvement.

Keywords: droplet-splitting; high throughput; microfluidics; microsphere; premixed emulsion.

Figure 1

CAD design of 512-channel geometrical droplet-splitting microfluidic device.

Figure 2

CAD designs of post array part for 512-channel geometric droplet-splitting microfluidic device: (a) type a, (b) type b, and (c) type c (unit: mm).

Figure 3

Microsphere preparation process of 512-channel geometric droplet-splitting microfluidic device by injecting premixed emulsion solution.

Figure 4

Pictures of dispersion test about ratio of water in mineral oil (3wt.% span 80): (a) after shaking and (b) 10 min, (c) microfluidic system with premixed emulsion. Optical images (d,e) and graph (f) of inherent droplet after shaking and 10 min.

Figure 5

Optical images of water droplets prepared using 512-channel geometric droplet-splitting microfluidic device using premixed emulsion solution at (a) 1st, (b) 2nd, (c) 3rd, (d) 5th, and (e) 6–9th T-junctions, and (f,g) collection part. (h) The graph of diameter and size distribution for the prepared micro water droplet (Q_mix = 10 mL/h).

Figure 6

(a) Dispersion test about the ratio of DMC solution with PVA solution, (b–d) optical images of PLGA micro droplet in microchannel, (e) SEM image and (f) diameter and size distribution of PLGA microsphere prepared by using injecting premixed emulsion at 10 mL/h.

Figure 7

Optical images of microdroplets prepared using 512 channel T-junction passive breakup device combined with a post array part according to the flow rate: 10 mL/h, 60 mL/h, and 100 mL/h: Type 1 (a–c), Type 2 (d–f), and Type 3 (g–i). The graphs of diameters and size distribution of micro water droplets with post array part (Q_mix = 20 mL/h): (j) Type 1, (k) Type 2, and (l) Type 3. and (m) diameter of water microdroplets according to flow rate of premixed emulsion with post array parts.

Figure 7

Optical images of microdroplets prepared using 512 channel T-junction passive breakup device combined with a post array part according to the flow rate: 10 mL/h, 60 mL/h, and 100 mL/h: Type 1 (a–c), Type 2 (d–f), and Type 3 (g–i). The graphs of diameters and size distribution of micro water droplets with post array part (Q_mix = 20 mL/h): (j) Type 1, (k) Type 2, and (l) Type 3. and (m) diameter of water microdroplets according to flow rate of premixed emulsion with post array parts.