Optofluidic chip for single cell trapping and stretching fabricated by a femtosecond laser

The authors present the design and optimization of an optofluidic monolithic chip, able to provide optical trapping and controlled stretching of single cells. The chip is fabricated in a fused silica glass substrate by femtosecond laser micromachining which can produce both optical waveguides and microfluidic channels with great accuracy. A new fabrication procedure adopted in this work allows the demonstration of microchannels with a square cross-section, thus guaranteeing an improved quality of the trapped cell images. Femtosecond laser micromachining emerges as a promising technique for the development of multifunctional integrated biophotonic devices that can be easily coupled to a microscope platform, thus enabling a complete characterization of the cells under test. [GRAPHICS] Glass substrate after femtosecond laser irradiation of six devices that will be obtained by six cuts along the transversal straight lines and a further orthogonal one. Chemical etching will create microchannels where the more complex structures have been irradiated, while not affecting the inscribed optical waveguides (slightly visible in the picture). The devices will then be used for optical trapping and stretching of cells.