Rich‐defect carbon nanotubes for highly sensitive detection of Dopamine

Abstract

Dopamine (DA) plays an essential role in the central nervous, renal, hormonal and cardiovascular systems. Various modified carbon nanotubes (CNT)‐based dopamine sensors have been reported, but inexpensive, highly sensitive plain CNT‐based ones are seldom studied. In this work, a facile and inexpensive CNT‐based DA sensor is made by rich‐defect multi‐walled carbon nanotubes (RD‐CNT) via an ultrasound method. The defect and elemental states of the RD‐CNT are systematically studied by transmission electron microscopy (TEM), high‐resolution transmission electron microscopy (HR‐TEM), Raman spectroscopy, X‐ray powder diffraction (XRD) and X‐ray‐photoelectron spectroscopy (XPS). Results show that massive holes and cracks exist in RD‐CNT. The level of defects increases from the additional exposed edges. The electrochemical characterizations indicate that the electrochemical sensor has the highest sensitivity of 438.4 μA/(μM ⋅ cm2) among all carbon materials‐based DA sensors while well meeting the clinically required detection range and selectivity. The DA sensor was further used to detect live healthy human serum and live PC12 cells with satisfactory results, thus holding great promise for an inexpensive but sensitive DA sensor in practical applications of clinical diagnosis and biological research.