Integration of digital microfluidics with whispering-gallery mode sensors for label-free detection of biomoleculesElectronic supplementary information (ESI) available. See DOI: 10.1039/c6lc01556e

• Main Authors: Wondimu, Sentayehu F, von der Ecken, Sebastian, Ahrens, Ralf, Freude, Wolfgang, Guber, Andreas E, Koos, Christian
• Format: Journal Article
• Language: English
• Published: 16.05.2017
• ISSN: 1473-0197; 1473-0189
• DOI: 10.1039/c6lc01556e

We present a multi-sensor chip comprising an array of whispering-gallery mode (WGM) micro-goblet lasers integrated into a digital microfluidic (DMF) system. In contrast to earlier demonstrations, the lasers are fabricated from dye-doped poly-methyl methacrylate (PMMA) at low cost using spin-coating, mask-based optical lithography, wet chemical etching, and thermal reflow techniques. Pumping and read-out of the devices is accomplished via simple free-space optics, thereby allowing large-scale sensor arrays to be addressed. We demonstrate the viability of the system by bulk refractive index-sensing and by measuring the specific binding of streptavidin to a biotinylated sensor surface. This is the first time that optical cavities are used for label-free detection of biomolecules in a DMF system. This approach can be extended to a versatile detector platform that targets a wide range of clinically relevant biomolecules. WGM biosensor arrays are integrated with a DMF system. The viability of the system is demonstrated by refractive-index and biosensing experiments.