Fabrication of Nanofilter Using Carbon Nanotubes for Microfluidic Chip

Abstract

This paper describes the fabrication of a simple and cost-effective nanofilter that can be applied to on-chip sample pretreatment for Lab-on-a-Chip. Previous work fabricating nanofilters for Lab-on-a-Chip includes micromachining with ion track technology, microbeads, and a polymer membrane. But, those are complex, expensive, or difficult to control pore size. We synthesize a nanofilter by entangling single-walled carbon nanotubes (SWNTs). Because pore size of CNT nanofilter can be readily controlled by varying CNT density and length, a CNT nanofilter is suitable for effective sample pretreatment. Individual nanotubes are converted to carboxylated SWNTs (SWNT-COOH) through chemical oxidation. SWNT-COOH are entangled each other by amide bonding among CNTs using 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS). We use a PDMS mold to make a specific shape of the CNT nanofilter required for Lab-on-a-Chip. The nanofilter incorporated into the can can used to concentrate biomolecules in a dilute solution or to separate the biomolecules based on size by microdialysis. This project is financially supported by the Future-Oriented Core Research Fund (2E19570) from the Korea Institute of Science and Technology (KIST).