Application of sulfur-doped graphene quantum dots@gold-carbon nanosphere for electrical pulse-induced impedimetric detection of glioma cells.

Ganganboina, Akhilesh Babu; Dega, Naresh Kumar; Tran, Hai Linh; Darmonto, Win; Doong, Ruey-An

Glioma is the predominant brain tumor with high death rate. The successful development of biosensor to achieve an efficient detection of glioma cells at low concentration remains a great challenge for the personalized glioma therapy. Herein, an ultrasensitive pulse induced electrochemically impedimetric biosensor for glioma cells detection has been successfully fabricated. The 4-11 nm sulfur-doped graphene quantum dots (S-GQDs) are homogeneously deposited onto gold nanoparticles decorated carbon nanospheres (Au-CNS) by Au-thiol linkage to form S-GQDs@Au-CNS nanocomposite which acts as dual functional probe for enhancing the electrochemical activity as well as conjugating the angiopep-2 (Ang-2) for glioma cell detection. Moreover, the application of an externally electrical pulse at +0.6 V expend the surface of glioma cells to accelerate the attachment of glioma cells onto the Ang-2-conjugated S-GQDs@Au-CNS nanocomposite, resulting in the enhanced sensitivity toward glioma cell detection. An ultrasensitive impedimetric detection of glioma cells with a wide linear range of 100-100,000 cells mL-1 and a limit of detection of 40 cells mL-1 is observed. Moreover, the superior selectivity with long-term stability of the developed biosensor in human serum matrix corroborates the feasibility of using S-GQDs@Au-CNS based nanomaterials as the promising sensing probe for practical application to facilitate the ultrasensitive and highly selective detection of cancer cells.