Light fueled mixing in open surface droplet microfluidics for rapid probe preparation.

In this study, a contactless, flexible, and interference-free light fueled method has been developed to enhance the mixing between the ssDNA and dynabeads in a droplet, which enables rapid probe preparation for promoting the probe technology based on open surface droplet microfluidics. In this light fueled method, the use of the photothermal effect of a focused infrared laser can easily create non-uniform temperature distribution and accordingly the surface tension gradient over the interface as a result of the localized heating effect, which thereby initiates the Marangoni flow in a droplet. Experimental results confirm that the light-induced Marangoni flow greatly enhances the mixing, ensuring rapid and efficient binding between the ssDNA and dynabeads. Moreover, the mixing intensity and degree can be simply tuned by controlling the laser intensity and laser heating time. The light fueled rapid mixing method developed in the present study paves the way for rapid bio-chemical detection.