Standardized bio-opto-fluidic chip technology using channel only process

Abstract

The integration of optical waveguides within biological assay chips seems to be an interesting solution to increase their functionality as it will allow local optical probing of the samples. However, the techniques proposed to build such chips are generally complex requiring multiple steps to fabricate waveguides and channels, and at the same time losing the capacity to use cost-effective fabrication technique like injection moulding. We propose a techniques where the waveguides are actually built as empty channel in the optical chip and later filled with special liquid to be used as waveguide. In this way, the chip only necessitates the fabrication of channels, some carrying the biological samples and others used as waveguides. To simplify further the fabrication, we developed a standard holder that allows to address the issue of filling the waveguide channel with the special liquid and at the same time provide connection for the sample testing. The chip was fabricated in PDMS and it was tested together with the standard holder using different liquids. Although the optical loss is still high due to scattering, this type of system was able to easily detect the bubbles appearing in a bi-phasic flow, opening the way for further improvements in the technology.