Electrochemical genosensor based on carbon nanotube/amine-ionic liquid functionalized reduced graphene oxide nanoplatform for detection of human papillomavirus (HPV16)-related head and neck cancer.

In continuing our effort focused towards the design and development of nanostructured carbon-based biosensors, herein we report an amine-ionic liquid functionalized reduced graphene oxide (NH2-IL-rGO) immunosensing nanoplatform for the electrochemical detection of human papillomavirus (HPV16) DNA in patients with HPV16-positive head and neck cancer (HNC). The model reaction considered in this work was based on grafting of IL to the surface of GO via its silylanization with 3-chloropropyltrimethoxysilane followed by N-alkylation with sodium imidazole salt. Then, the obtained NH2-IL-rGO was immobilized on a multiwalled carbon nanotube (MWCNT) modified electrode surface and, subsequently used for loading aminated DNA probes via covalent bonds by the glutaraldehyde (GA) reagent. In the presence of anthraquinone-2-sulfonic acid monohydrate sodium salt (AQMS) as a redox-active DNA intercalator, the hybridization of ssDNA probes with the target HPV16 DNA strands (complementary strands) led to a significant increase in the genosensor response. The strong specific interaction between the immobilized probe chain and the complementary chain enabled the detection of the HPV16 gene with the differential pulse voltammetry (DPV) measurements. The described method provided an excellent accuracy and good selectivity, compared to the existing methods. This low-cost genosensor can detect ultralow concentrations of HPV16 DNA with a limit of detection of 1.3 nM (at 3σ) and a linear range of 8.5 nM-10.7 μM. To validate the accuracy and performance of method, the extracted clinical sample DNA was used on the pDNA-modified electrode unlike other works that used PCR products.