Fabrication of Microfiber-Templated Microfluidic Chips with Microfibrous Channels for High Throughput and Continuous Production of Nanoscale Droplets

A polydimethylsiloxane (PDMS) microfluidic chip with wellinterconnected microfibrous channels was fabricated by using an electrospun poly(e-caprolactone) (PCL) microfibrous matrix and 3D-printed pattern as templates. The microfiber-templated microfluidic chip (MTMC) was used to produce nanoscale emulsions and spheres through multiple emulsification at many small micro-orifice junctions among microfibrous channels. The emulsion formation mechanisms in the MTMC were the cross-junction dripping or Yjunction splitting at the micro-orifice junctions. We demonstrated the high throughput and continuous production of water-in-oil emulsions and polyethylene glycol-diacrylate (PEG-DA) spheres with controlled size ranges from 2.84 mu m to 83.6 nm and 1.03 mu m to 45.7 nm, respectively. The average size of the water droplets was tuned by changing the micro-orifice diameter of the MTMC and the flow rate of the continuous phase. The MTMC theoretically produced 58 trillion PEG-DA nanospheres per hour without high shear force. In addition, we demonstrated the higher encapsulation efficiency of the PEG-DA microspheres in the MTMC than that of the microspheres fabricated by ultrasonication. The MTMC can be used as a powerful platform for the large-scale and continuous productions of emulsions and spheres.

Automated summary

In this study, a polydimethylsiloxane (PDMS) microfluidic chip with well-interconnected microfibrous channels was fabricated using electrospun poly(e-caprolactone) (PCL) microfibrous matrix and 3D-printed patterns as templates. The chip, known as microfiber-templated microfluidic chip (MTMC), demonstrated high throughput and continuous production of nanoscale emulsions and spheres by utilizing mechanisms such as cross-junction dripping and Y-junction splitting. The MTMC allows for controlled size ranges of water-in-oil emulsions and polyethylene glycol-diacrylate (PEG-DA) spheres, and can potentially produce 58 trillion PEG-DA nanospheres per hour without high shear force. Additionally, the MTMC showed higher encapsulation efficiency compared to microspheres fabricated by ultrasonication, making it a powerful platform for large-scale and continuous production of emulsions and spheres.