A durable and miniature microfluid device for detection of aggregation-induced emission molecules

Abstract

An aggregation-induced emission (AIE) molecules detecting device was proposed. It was a microfluid sensor, fabricated with Teflon AF 2400 capillary and micromachining technique. The Teflon capillary played three roles in the detecting system simultaneously: the microfluid channel, the optical waveguide and the fluorescence collector. The microfluid channel was formed by a laser ablated micro hole and an open capillary end. The optical waveguide and the fluorescence collector were functionalized by the particular refractive index (RI) of the capillary, which was 1.29, lower than water (RI: 1.33). When filled with AIE solution, the Teflon capillary had a RI distribution of inner higher and outer lower which form an optical waveguide. Then the excited fluorescence was collected and transmitted within it. The length of capillary was optimized through an experimental method. With an optimized device, the fluorescence intensity depending on the concentration was tested. The experimental results were in accordance with the traditional micro plate spectrophotometer methods. The limit of detection (LOD) was obtained as 3.94 μM with only 1.946 μl volume solutions, better than previous works. The bending loss of the device was also examined. With the curvature of 10.3 m−1, only 13% transmission loss was detected which means the sensing device could be expected to apply in vivo. In addition with the advantages of small size and durable structure, the proposed device has bright future in many biosensing applications.