Internal to External Microfluidic Device for Ellipsometric Biosensor Application

The femtosecond pulses offer a flexible way to induce internal modifications inside fused silica and prepare embedded 3D microchannel structures. In this paper, an internal to external microfluidic device is presented. The micro-channels were prepared with the direct laser writing technique using different scanning methods. The sample was immersed in diluted 10 % concentration HF acid to remove the modified material. A few independent 3D microchannels were inscribed, and each of them was connected to a pump to circulate the protein solution during the measurement preserving a constant flow rate. Microchannels were designed to act as flow cells in ellipsometric imaging surface plasmon resonance (iSPR) setup to study the real-time interaction kinetics of biological materials (proteins or DNA). The microchannels allow to make few parallel measurements at the same time and minimize the required biological sample amounts for the iSPR experiment.