Review Ultrafast Laser Fabrication of Functional Biochips: New Avenues for Exploring 3D Micro- and Nano-Environments Felix Sima 1,2,*, Jian Xu 1, Dong Wu 1,3 and Koji Sugioka 1,* 1 RIKEN Center for Advanced Photonics, Wako, Saitama 351-0198, Japan;
[email protected] 2 Center for Advanced Laser Technologies (CETAL), National Institute for Laser, Plasma and Radiation Physics (INFLPR), Atomistilor 409, 0077125 Magurele, Romania 3 University of Science and Technology of China, Hefei 230026, China;
[email protected] * Correspondence:
[email protected] (F.S.);
[email protected] (K.S.); Tel.: +81-48-467-9495 (F.S./K.S.) Academic Editors: Roberto Osellame and Rebeca Martínez Vázquez Received: 21 December 2016; Accepted: 25 January 2017; Published: 28 January 2017 Abstract: Lab-on-a-chip biological platforms have been intensively developed during the last decade since emerging technologies have offered possibilities to manufacture reliable devices with increased spatial resolution and 3D configurations. These biochips permit testing chemical reactions with nanoliter volumes, enhanced sensitivity in analysis and reduced consumption of reagents. Due to the high peak intensity that allows multiphoton absorption, ultrafast lasers can induce local modifications inside transparent materials with high precision at micro- and nanoscale. Subtractive manufacturing based on laser internal modification followed by wet chemical etching can directly fabricate 3D micro-channels in glass materials. On the other hand, additive laser manufacturing by two-photon polymerization of photoresists can grow 3D polymeric micro- and nanostructures with specific properties for biomedical use. Both transparent materials are ideal candidates for biochips that allow exploring phenomena at cellular levels while their processing with a nanoscale resolution represents an excellent opportunity to get more insights on biological aspects.