Figure 1.

Schematic of the silk particle fabrication device. (A) Process for silk particle fabrication via co-flow and flow-focusing microfluidics device. The fluids (silk solution as the internal phase; PVA solution as the external phase) flow through the device using syringe pumps. The output is collected in a petri dish and allowed to evaporate overnight. The result film is dissolved to separate the silk particles and remove soluble polymers. (B) Larger schematic view of the flow-focusing device. The two solutions (the external phase: purple arrow; the internal phase: green arrow) flow into the device through the inlets (i) and meet at the flow-focusing channel device (ii). They then flow together through the serpentine (iii) until they exit the device through the outlet (iv; blue arrow). (C) Stereoscope image of the two solutions flowing through the device with the PVA solution dyed with food coloring to provide contrast. The flow-focusing channel device width, the internal phase flow rate, polymer concentrations, and silk molecular weight were the process variables for this study.