A label-free sensor based on a carbon nanotube-graphene platform for the detection of non-Hodgkin lymphoma genes

Abstract

Early diagnosis of non-Hodgkin lymphoma (NHL) is crucial for effective management. We report an ultrasensitive electrochemical genosensor using multi-walled carbon nanotube (MWCNT)-graphene nanocomposite for detection of lymphoma biomarker gene. MWCNTs were dispersed over graphene nanoplatelets to form a conductive nanocomposite platform. The high surface area and π-π stacking ability enabled efficient immobilization of lymphoma probe DNA. Detailed materials characterization was performed using microscopy and spectroscopy techniques. The sensor was fabricated by drop-casting probe-conjugated nanocomposite suspension onto a glassy carbon electrode. The genosensor exhibited a wide dynamic range of 1 fM to 1 nM with a sensitivity of 0.895 kΩ per decade of target concentration. The sensor showed excellent selectivity for fully complementary target sequence over even single base mismatch. Hybridization detection by electrochemical impedance spectroscopy was further validated using differential pulse voltammetry which showed drastic reduction in redox peak current after incubating with target. The nanocomposite genosensor demonstrated good reproducibility with relative standard deviation of 3.72 % among five independently prepared electrodes. Clinical applicability was tested by spiking lymphoma gene biomarker in 10 % serum and recoveries of 93–99 % were obtained. The proposed MWCNT-graphene nanocomposite genosensor provides a simple, specific and ultrasensitive platform for point-of-care diagnosis of NHL.

Keywords

• Electrochemical genosensor
• Non-Hodgkin lymphoma
• Carbon nanotubes
• Graphene
• Impedimetric detection