A microfluidic chip for biomimicking the spinning duct of silk worm

摘要

In this article, a microfluidic channel (500 μm in width, 100 μm in depth) in a micro-chip was fabricated in poly-(dimethylsiloxane) (PDMS) on a SU-8 mold based on photolithography process. By biomimicking the glands and the spinning ducts of silk worms, this chip was designed and used to adjust the pH and the concentration of Ca2+of regenerated silk fibroin (RSF) aqueous solution. Due to the laminar flow characteristic of microfluidics, the RSF solution and a pH buffer tended to keep their laminar streams without mixing. Thus, the RSF concentration was maintained while the pH of the RSF solution was adjusted during flow via ionic diffusion. The results showed that it was easier to adjust the pH of the RSF aqueous solution to the target pH of the buffer, when the two streams had closer pHs or lower flow rates. Our initial result suggested that it is also possible to adjust the concentration of Ca2+of the RSF aqueous solution during flow. The experiments indicated that this chip might also be applied for the multicomponents adjustment of RSF solution during flow, (such as contents of various metal irons and pH), and further studies on the assembly mechanism of RSF.