Carbon nanotube-based labels for sensitive nucleic acids detection

Abstract

A novel multiple-labelled conjugate with carbon nanotubes (CNTs) to amplify hybridization signal was developed to improve the nucleic acids assay sensitivity. The carboxylated CNTs were functionalized by horseradish peroxidase (HRP) and single-stranded oligonucleotides via diimide-activated amidation. Oligonucleotides with specific sequence from SUP-B15 cell line that serves as molecular signatures of human acute lymphocytic leukemia (ALL) was synthesized and used as targets. Results show that both HRP and oligonucleotides were conjugated to the CNTs. The resulting conjugates can hybridize to its complementary targets and function as a label for nucleic acid quantification. These labels are also able to amplify the signals generated by the colorimetric method that significantly enhance the detection limit of the target by at least 1000 folds compared with conventional labels. These labels offer a unique advantage. Visual inspection of target detection was made possible due to the formation of visible aggregates.