Spinning webs with microfluidics

Spiders produce their silk threads by generating a liquid that solidifies when exposed to air. Inspired by this process, Sanghoon Lee and co-workers at Dankook University, Cheonan, and Hanyang University, Seoul, in collaboration with David Beebe and colleagues at the University of Wisconsin, Madison, have developed a microfluidic system that can produce microscale structures in a similar way.

While spiders’ silk solidifies on exposure to air, the polymeric structures produced by Lee’s system solidify on exposure to light. The new technique avoids the need to rely on some form of 3D construct, that traditional methods need.

The technique combines 3D multiple stream laminar flow and ’on-the-fly’ in situ photopolymerisation. This means that the polymerised fibre can move through the device in the same direction as the flow without touching the channel’s inner surface. It then emerges from the device as a solid polymerised fibre.

Fibres and tubes of all shapes and sizes can be made simply by changing the channels in the system. By controlling the sample and sheath volume flow rates, the fibre dimensions can be altered without re-tooling the channels. This makes the device very versatile - a single system has produced both stimuli-responsive woven fabric and biosensing fibres. The authors believe the technique has the potential to be widely used in many different fields.

Rowena Milan