Lasers for nano scaffolds

Finnish researchers have developed a direct-write three-dimensional method of forming biomaterials into microscopic scaffolds that can be used to rebuild body tissue.

VTT Technical Research Centre of Finland, Tampere University of Technology and Nanofoot Finland developed the methodology which enables the fabrication of nano and micrometre scale structures that can be used as parts of tissue engineering scaffolds. The project is funded by the BioneXt Tampere Research Programme.

The new process is based on the use of visible light, ultra short pulse laser. When focused inside photopolymerisable material the radiation causes a reaction, where two photons are absorbed simultaneously, leading to the polymerisation of the material.

One of the advantages of this two-photon polymerisation process is that the fabrication occurs below the surface of liquid material, and the polymerisation is confined only to the point of focus whose diameter can be much less than one micrometre. Conventional ultraviolet light induced polymerisation causes hardening of the material along the entire path of the UV-beam, making it impossible to form very small three-dimensional features. The two photon polymerisation process requires no utilisation of special photolithographic masks since the structure is formed directly inside the liquid volume.