Laser-based technique builds 3D micron-scaled structures

Known as 3D photografting, the system uses a focused laser as a kind of paint brush to set off chemical signals that direct compounds or cells to the chosen point within a block of material.

The researchers are from two teams that have previously worked on 3D printing — one from the university’s materials science department, led by Prof Jürgen Stampfl, and the other from a macromolecular chemistry research group led by Prof Robert Liska.

The technique, however, is not related to 3D printing, but is a development of a method previously used to modify the surface of a polymer.

The team started with a macomolecular hydrogel, a polymeric substance with a very low density whose structure is an open lattice with large pores. They seeded this structure with aromatic azide molecules, then irradiated the hydrogel with a laser focused to a point 4µm across. The light transforms the azide molecules into highly reactive groups onto which specific compounds will attach very quickly.