Our research goal is laser fabrication of microfluidic devices such as Lab-on-a-Chip, their physical-chemical investigation, assembling and in vitro testing for biomedical applications. Current studies are devoted to developing models for blood brain barrier pathology and cancer metastasis. We are developing 3D microstructures (cell chambers interconnected by channels) inside glass and hybrid PDMS/glass biochips. Microwell biochips fabrication for single cell trapping and analyses is also possible, reducing microchambers volume down to <1 nL. Other application is the fabrication of biochips for droplets microfluidics.

I. Biochips/biowells microfabrication is based on a technology developed by us (picosecond laser-assisted etching-PLAE), consisting in three successive steps, as schematically presented in the figure below:
1. 3D laser direct writing of glass using picosecond laser pulses is performed using a custom-made laser processing platform.
2. Samples are submitted to a controlled thermal annealing in a programmable furnace.
3. Glass samples are submitted to chemical etching in a diluted HF solution under the ultrasonic condition.

II. Some representative examples of a large-scale biochip embedding 3D nanochanels and microwell arrays are presented in the following.

III. Immunofluorescence microscopy images of Mesenchymal Stem Cells grown on glass samples developed by PLAE, with (left) and without (right) collagen coating is presented below.

Relevant publications:

• Sima, F.; Kawano, H.; Hirano, M.; Miyawaki, A.; Obata, K.; Serien, D.; Sugioka, K. Mimicking intravasation–extravasation with a 3d glass nanofluidic model for the chemotaxis-free migration of cancer cells in confined spaces. Adv. Mater. Technol. 2020, 2000484. https://doi.org/10.1002/admt.202000484
• Jipa, F.; Orobeti, S.; Butnaru, C.; Zamfirescu, M.; Axente, E.; Sima, F.; Sugioka, K. Picosecond Laser Processing of Photosensitive Glass for Generation of Biologically Relevant Microenvironments. Appl. Sci. 2020, 10, 8947. https://doi.org/10.3390/app10248947
• Jipa, F.; Iosub, S.; Calin, B.; Axente, E.; Sima, F.; Sugioka, K. High Repetition Rate UV versus VIS Picosecond Laser Fabrication of 3D Microfluidic Channels Embedded in Photosensitive Glass. Nanomaterials 2018, 8, 583. https://doi.org/10.3390/nano8080583

Ongoing collaborations:

• RIKEN Center for Advanced Photonics, Japan.
• Department of Molecular Cell Biology, Institute of Biochemistry, Romanian Academy, Bucharest, Romania.
• Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, Romania.
• Department of Life and Environmental Physics, ‘Horia Hulubei’ National Institute for Physics and Nuclear Engineering, Măgurele, Romania.
• Biophysics and Cellular Biotechnology Dept. and Excellence Centre for Research in Biophysics and Cellular Biotechnology, University of Medicine and Pharmacy Carol Davila, Romania.