Digital Microfluidics with Bubble Manipulations by Dielectrophoresis

Abstract

This paper presents a novel method for fabricating PDMS‐based optical leaky waveguides coated with self‐assembled gold nano‐particles (Au‐NP) for bio‐analytical detection utilizing the localized surface plasmon resonance (LSPR) effect. In the presented method, a PDMS optical waveguide is first cast in Teflon tubing to form a cylindrical leaky waveguide structure. The de‐molded PDMS optical waveguide is then modified with PDDA molecules and coated with a layer of 13 nm Au‐NPs for inducing the LSPR effect. The fabricated LSPR sensor is finally connected to multi‐mode optic fibers for guiding the detection light. The measured sensitivity of the PDMS waveguide based LSPR sensor for detecting diluted glycerol solutions was 7.25 AU/RIU and 325.97 nm/RIU. Experimental results of a label‐free detection of DNA hybridization show that the presented PDMS waveguide based LSPR sensor has a good linear response and has a detection limit of about 10pM, confirming the detection performance of the developed PDMS waveguide‐based LSPR sensor.