Laser Initiated Reactions

Laser-induced click chemistry reactions. The transfer of biomaterials (such as aptamers), by laser-induced forward transfer (LIFT), induces their covalent bonding by thiol−ene or thiol−yne reactions that occur upon UV irradiation of the thiol-modified aptamers, on the chemically modified surfaces, with ns laser pulses. This combination of LIFT and laser-induced click chemistry allows the creation of high resolution patterns without the need for masks. Whereas the click chemistry already takes place during the printing process (single-step process) by the same laser pulse used for the printing process, further irradiation of the LIFT-printed biomaterials by laser pulses (two-step process) leads to a further increase in the immobilization efficiency.

Dual laser beam approach - LIFT and laser photopolymerization of hydrogels. For the creation of 3D hydrogel structures, we follow a 2 step process according to which, in the first step we use a UV laser pulse to print a droplet of the biomaterial-monomer solution and in an additional step a second laser pulse is irradiating the printed droplets so as to photo-polymerize the solution and get the hydrogel structure. With this technique, we are able to have spacial control on the created structures and thus create highly sophisticated bio-structures with various sizes and control the thickness of the polymer film by laser pulses.

Laser Bioprinting for sensor applications

The accuracy and the flexibility of LIFT technique enabled precise transfer of antibodies on different asymmetric Mach Zehnder Interferometers (aMZIs), for the multiplex detection or protein cancer biomarkers in blood samples. This is part of an EU H2020 project, named BIOCDx, aiming to develop a miniaturized, ultra-sensitive and reliable Complementary Diagnostics device with disposable microfluidic cartridge for the monitoring of cancer biomarkers in body fluids and specifically in whole blood samples.

Laser Induced Immobilization of Biomaterials

One of the most crucial steps for the development of bio-sensors is the immobilization of the biomaterial onto the sensor surface. LIFT has been proven an advanced tool for direct immobilization of biomaterials on low cost non-functionalized screen printed electrodes. The high kinetic energy of the transferred material enhances physical adsorption onto the electrode surface and results in high activity by using extremely low quantities of biomaterials. At NTUA, the direct immobilization of biomaterials is mainly used for sensor applications but also for the responsible physical mechanisms are studied.

Laser printing of cells

At NTUA we combine natural and/or synthetic scaffolds with LIFT for the placement of specific cell types into specific locations, leading to the development of novel 3D tissue models and cell constructs whose sophistication lies beyond the current state of the art.