N-Doped Graphene Quantum Dots Confined within Silica Nanochannels for Enhanced Electrochemical Detection of Doxorubicin

Abstract

Herein, we describe a fast and highly sensitive electrochemical sensor for doxorubicin (DOX) detection based on the indium tin oxide (ITO) modified with a binary material consisting of vertically-ordered mesoporous silica films (VMSFs) and N-doped graphene quantum dots (NGQDs). VMSFs, with high permeability and efficient molecular transport capacity, is attached to the ITO electrode via a rapid and controllable electrochemical method, which can serve as a solid template for the confinement of numerous NGQDs through facile electrophoresis. By virtue of the excellent charge transfer capacity, π-π and electrostatic preconcentration effects of NGQDs, as well as the electrostatic enrichment ability of VMSF, the presented NGQDs@VMSF/ITO shows amplified electrochemical signal towards DOX with a positive charge, resulting in good analytical performance in terms of a wide linear range (5 nM~0.1 μM and 0.1~1 μM), high sensitivity (30.4 μA μM−1), and a low limit of detection (0.5 nM). Moreover, due to the molecular sieving property of VMSF, the developed NGQDs@VMSF/ITO sensor has good selectivity and works well in human serum and urine samples, with recoveries of 97.0~109%, thus providing a simple and reliable method for the direct electrochemical analysis of DOX without complex sample pretreatment procedures.

Solid Electrochemiluminescence Sensor by Immobilization of Emitter Ruthenium(II)tris(bipyridine) in Bipolar Silica Nanochannel Film for Sensitive Detection of Oxalate in Serum and Urine

“…On the other hand, the silica structure of SNA is rich in silanol groups. The low p K a (~2) allows it to ionize in commonly used buffer media, forming a negatively charged surface [ 48 , 49 ]. Consequently, SNA-modified electrodes exhibit charge-based selectivity, electrostatically repelling negatively charged small molecules while attracting positively charged ones.…”

Sensitive Electrochemical Detection of Carcinoembryonic Antigen Based on Biofunctionalized Nanochannel Modified Carbonaceous Electrode

“…Furthermore, vertically ordered mesoporous silica film (VMSF) has received considerable attention [ 26 , 27 , 28 , 29 ]. VMSF has high-porosity, vertically ordered nanochannels with a size from 2 to 3 nm [ 30 , 31 , 32 , 33 ]. These characteristics give VMSF a fast mass transfer ability and selectivity based on size and charge [ 32 , 33 , 34 , 35 ].…”

Vertical Silica Nanochannels and o-Phenanthroline Chelator for the Detection of Trace Fe(II)

“…However, these methods often rely on trained operators, expensive equipment, and tedious preprocessing, despite providing accurate and satisfactory results. Electrochemical sensors have attracted great attention due to their superiority of high sensitivity, outstanding selectivity, fast response, easy integration, and in situ monitoring, which have been developed into powerful analytical tools in the fields of environmental protection and biomedicine. − To enhance the electrochemical sensing performance of iron, a variety of nanomaterials are developed and assembled on the electrode to introduce multifunctions, such as catalysis, surface coordination, separation, preconcentration, switching, and target recognition . On the basis of the complexation and preconcentration, dimethyliminocinnamyl-linked rhodamine and a kind of imine receptor prepared from 4,4′-diaminodiphenymethane and 2-hydroxy-5-nitrobenzaldehyde have been reported and modified on the substrates to provide nitrogen atoms as donor species to bind Fe 2+ , respectively, showing excellent selectivity and outstanding quantitative capability.…”