Abstract

An Opto-Microfluidic Lab-on-a-Chip in Lithium Niobate for Protein Concentration Analysis

Leonardo Zanini, PhD student, University of Padova

Lab-on-a-chips integrating microfluidics and optics set a new frontier in biological sample processing, merging miniaturization with real-time content analysis. This presentation shows an example of such an opto-microfluidic lab-on-a-chip and its application to protein concentration investigation. The integration is achieved herein by placing on the same substrate surface in lithium niobate both an array of parallel waveguides and a cross of two micrometric channels. After realizing the waveguides, the longer channel is engraved to break perpendicularly each waveguide in its middle, dividing each guide into two collinear ones. Once light is carried through one waveguide, the optical interaction with the microdroplets flowing in the channel generates a signal collected by the opposite waveguide and strictly related to the droplet shape and content. In this research, different concentrations of a chosen protein are encapsulated in microdroplets to be studied through the chip, applying the well-known Bradford protocol for protein concentration investigation. By fixing the droplet geometry, the content information is extrapolated directly from the acquired signals through a comparison with an appropriate baseline. The calibration of this detection method will be presented together with experimental results and perspectives, proving the chip as an efficient integrated sensor for content analysis.