Magnetic multiwalled carbon nanotubes as nanocarrier tags for sensitive determination of fetuin in saliva

Abstract

This paper reports the development and performance of an electrochemical immunosensor using magnetic multiwalled carbon nanotubes (m-MWCNTs) as nanocarrier tags for the determination of human fetuin A (HFA), a relevant biomarker of obesity, insulin resistance, and type-2 diabetes as well as for pancreatic and liver cancers and inflammatory processes. Screen-printed carbon electrodes were grafted with p-aminobezoic acid and streptavidin was covalently immobilized on the electrode surface. A biotinylated capture antibody was immobilized through streptavidin-biotin interaction and a sandwich assay configuration was implemented using m-MWCNTs conjugated with HRP and anti-HFA antibodies as the detection label. The determination of HFA was accomplished by measuring the current produced by the electrochemical reduction of benzoquinone at -200 mV upon addition of HO as HRP substrate. The prepared m-MWCNTs were characterized by SEM, TEM, XRD and EDS. All the steps involved in the immunosensor preparation were monitored by electrochemical impedance spectroscopy and cyclic voltammetry. A linear calibration plot for HFA was found between 20 and 2000 pg/mL with a LOD value of 16 pg/mL. This performance is notably better than that reported for an ELISA kit and a chronoimpedimetric immunosensor. The favorable contribution of m-MWCNTs in comparison with MWCNTs without incorporated magnetic particles to this excellent analytical performance is also highlighted. The immunosensor selectivity against other proteins and potentially interfering compounds was excellent. In addition, the usefulness of the immunosensor was demonstrated by the analysis of HFA in saliva with minimal sample treatment.

Binary MoS2 nanostructures as nanocarriers for amplification in multiplexed electrochemical immunosensing: simultaneous determination of B cell activation factor and proliferation-induced signal immunity-related cytokines

“…MoS 2 /MWCNTs(-HRP)-dAbs carrier tags were prepared through a similar protocol to that reported previously for the preparation of other nanocarriers involving MWCNTs hybrids [ 18 , 23 , 24 ]. Briefly, 500 μL of 0.1 mg mL −1 MoS 2 /MWCNTs was centrifuged at 14,000 rpm during 10 min and the remaining product was incubated in the darkness under continuous stirring for 6 h at room temperature with 200 μL of a 400 mM EDC and 100 mM NHSS mixture solution prepared in 100 mM PBS pH 7.4.…”

Non-Invasive Electrochemical Biosensors Operating in Human Physiological Fluids

“…Another approach was made, by using magnetic multiwalled carbon nanotubes as nanocarrier tags for the detection of human fetuin A with impedimetric read out. Moreover, the electrochemical immunosensor was realized by using the linker molecule diazonium, followed by the immobilization an anti-human fetuin A-antibody and coupled HRP [131].…”

Application of Microfluidics in Biosensors

“…The most commonly adopted physiological fluids of human beings/animals are blood, which has to be collected in an invasive way, and fluids that can be collected in a noninvasive way, e.g., sweat, saliva, tears, and urine, can be used in the prediction and diagnosis of various diseases [75][76][77]. Comparing with other physiological fluids, saliva is the outstanding fluid with the advantages of easy accessing and large volume, but with a major disadvantage of large range of variability in components and concentrations depending on the extent of oral cleanliness; examples that have been experimentally verified are using human saliva for the detection of cytokine [78], dopamine [51], insulin [79], fetuin [80], bacterial load [81], cholesterol [25], and cortisol [82]; using tear for the detection of dopamine [83], proteomic, lipidomic, and metabolomic composition [77]; using sweat for the detection of cytokine [84] and proteomic [76]; and using urine for the detection of anticancer drugs [85], L-carnitine [86], Chlamydia trachomatis, and Neisseria gonorrhoeae [87]. Samples of sweat and tear have been significantly undeveloped until quite recent when flexible materials and flexible electronic techniques achieved some milestones [4].…”