Direct laser writing with ultrashort laser pulses is a promising three-dimensional microfabrication method that has recently attracted considerable attention. When focused into the volume of a photosensitive material (or photoresist), the ultrashort pulses initiate a multi-photon absorption process that leads to a very localized polymerization. After illumination of the desired structures inside the photoresist volume and subsequent development — e.g., washing out the non-illuminated regions — the polymerized material remains in the prescribed 3-D form. This allows fabrication of any computer-generated 3-D structure by direct laser writing into the volume of a photosensitive material.
Because of the threshold behavior and nonlinear nature of the process, a resolution beyond the diffraction limit can be achieved by tailoring the irradiation conditions.
At IFN-CNR we have a long tradition in direct laser writing, with two homebuild setups targeting several applications. Current trends include the development of 3D scaffolds for cell proliferation and differentiation, the fabrication of lab-on-chip with engineered constrictions for cell motility studies and the realization of microlenses with arbitrary profile.
On-going projects:
European funded project (FET) In2Sight in collaboration with Politecnico di Milano
Selected publications:
- C. Conci et al. “A Miniaturized Imaging Window to Quantify Intravital Tissue Regeneration within a 3D Microscaffold in Longitudinal Studies,” Advanced Optical Materials 10, 2101103 (2022). Link
- F. Sala, et al. “Microfluidic Lab-on-a-Chip for Studies of Cell Migration under Spatial Confinement,” Biosensors 12, 604 (2022). Link
- C. A. Musi et al. “Effect of 3D Synthetic Microscaffold Nichoid on the Morphology of Cultured Hippocampal Neurons and Astrocytes,” Cells 11, 2008 (2022). Link
- L. Kelemen et al. “Direct writing of optical microresonators in a lab-on-a-chip for label-free biosensing,” Lab Chip 19, 1985 (2019). Link
- T. Zandrini et al. “Multi-foci laser microfabrication of 3D polymeric scaffolds for stem cell expansion in regenerative medicine” Scientific Reports 9, 11761 (2019). Link
- M. T. Raimondi et al. “Three-dimensional structural niches engineered via two-photon laser polymerization promote stem cell homing,” Acta Biomaterialia 9, 4579–4584 (2013). Link
- L. Amato et al. “Integrated three-dimensional filter separates nanoscale from microscale elements in a microfluidic chip,” Lab Chip 12, 1135-1142 (2012). Link
