Study on optical response sensitivity in hybrid of single-walled carbon nanotubes mixed with double-stranded DNA and carboxymethylcellulose

Abstract

This study investigated the optical response sensitivity of a hybrid of single-walled carbon nanotubes (SWNTs) mixed with double-stranded DNA (dsDNA) and carboxymethylcellulose (CMC). The changes of optical response in SWNTs such as oxidation and antioxidant reactions can be measured using near infrared (NIR) absorbance spectra. The previous studies have not identified a sensitivity of mixture ratio of CMC and dsDNA for optical response of SWNTs. SWNTs hybrids prepared by mixing dsDNA and CMC were oxidized by H2O2 for 30 min (final concentration 0.03%), and then antioxidized by catechin (final concentration 15 μg/mL) hybrid for 10 min. The NIR absorbance of SWNT hybrids was shown to be sensitive even when mixed with dsDNA at a weight concentration (mg/mL) of 1% CMC. While the optical response of SWNTs was highly dependent on the mixture ratio of DNA and CMC, there was no significant difference in the height distribution of SWNTs hybrids examined by atomic force microscopy (AFM). This result suggests that the optical response performance of dsDNA/CMC-SWNTs hybrids sensor can be greatly controlled by the mixture ratio of dsDNA and CMC without changing the heights of the hybrids.