Covalent conjugation of reduced graphene oxide with oligos for current–volt signal determination on leukemia

Abstract

Oncogene-mutated breakpoint cluster region protein gene (BCR/ABL) has been found in chronic myelogenous leukemia (CML) patients. In particular, b3a2 is a common mutation type with CML, tested in this research as deoxyribonucleic acid sensor to identify the specific b3a2 sequence by a suitable capture probe. The aminated capture probe was attached on interdigitated electrode surface through the chemical linker, glycidyloxypropyltrimethoxysilane. Covalently linked reduced graphene oxide (rGO) with target sequence was identified by the capture probe. The prepared rGO from vacuum-assisted low-temperature exfoliated graphite was characterized by field emission scanning electron microscope, field emission transmission electron microscope, energy-dispersive X-ray spectroscopy and fourier-transform infrared spectroscopy. The limit of detection with duplex formation was attained between 1 and 10 aM, and the saturation point was noticed from 10 fM. The sensitivity was calculated to be 1 aM. Further, control experiments with single-, triple- and complete mismatch-sequences instead of target complementary failed to yield the changes in current signal indicating the selective identification of targeted b3a2 sequence. This method of detection helps in identifying the minimal leukemia cells residual with CML patient.