Highly porous magnetite/graphene nanocomposites for a solid-state electrochemiluminescence sensor on paper-based chips

Abstract

Graphene-nanosheet-based highly porous magnetite nanocomposites (GN-HPMNs) have been prepared using a simple solvothermal method and used as an immobilization matrix for the fabrication of a solid-state electrochemiluminescence (ECL) sensor on paper-based chips. Highly porous Fe3O4 nanocrystal clusters were coated with acrylate and wrapped tightly on the skeleton of graphene nanosheets. The structures and sizes of the GN-HPMNs could be tuned by varying the proportions of the solvents ethylene glycol and diethylene glycol. Then, the relatively highly porous ones with an average diameter of about 65 nm were combined with Nafion to form composite films on an electrode surface for immobilization of Ru(bpy)3(2+) (bpy is 2,2'-bipyridine). Because of their porosity, negatively charged surface, and cooperative characteristics of magnetic nanomaterials and graphene, under an external magnetic field, the GN-HPMNs ensured effective immobilization, excellent electron transfer, and long-term stability of Ru(bpy)3(2+) in the composite film. The sensor developed exhibited excellent reproducibility with a relative standard deviation of 0.65% for 30 continuous cycles. It was found to be much more favorable for detecting compounds containing tertiary amino groups and DNAs with guanine and adenine. A detection limit (signal-to-noise ratio of 3) of 5.0 nM was obtained for tripropylamine. As an application example, 0.5 nM single-nucleotide mismatch could be detected. This was the first attempt to introduce magnetic nanomaterials and an external magnetic field into paper-based chips. The sensor developed has the advantages of high sensitivity, good stability, and wide potential applicability as well as simplicity, low cost, and good disposability.

Electrochemiluminescence Detection in Paper‐Based and Other Inexpensive Microfluidic Devices

“…Reports on these detection methods can be found in the literature. [30][31][32][33][34] Erin M. Gross received her B.S. degree in Chemistry from Creighton University (USA) and went on to obtain her Ph.D. degree in Chemistry from the University of North Carolina at Chapel Hill (USA) under the mentorship of R. Mark Wightman.…”

New Design forDetection Cell Applied in Magnetic Particle‐Based Electrochemiluminescence Assays

“…CMNs were synthesized through a modified solvothermal reaction at 200 8C by reduction of FeCl 3 with ethylene glycol (EG) in the presence of sodium acetate as an alkali source and biocompatible trisodium citrate as an electrostatic stabilizer [9]. GHPMNs were fabricated through solvothermal reaction of FeCl 3 ·6H 2 O with sodium acetate and sodium acrylate and simultaneous reduction graphene oxide in the mixed solvent of EG and diethylene glycol (DEG) (EG/DEG = 1/ 4.3) [10]. The new ECL detection cell was fabricated from Teflon by Computer Numerical Control (CNCIAC-55, Good CNC Machine Co., Ltd., China).…”

“…Apparently, the diffusion coefficients of 0.1 mM Ru(bpy) 3 2 + had no significant change in the presence of the CMNs (Figure 2b) and just a little decrease with additional magnetic force (Figure 2c), while increased at the ITO electrode after adding 7.0 mg/mL GHPMNs, especially with the external magnetic force. It means that the rate at which Ru(bpy) 3 2 + diffuses to the surface of the electrodes was accelerated in the presence of GHPMNs due to the amplification effects of graphenebased MPs on ECL [10], and the magnetic force enhanced the effects on ECL systems at most.…”

“…Based on the cell, effects of two well-studied MPs with and without graphene (CMNs [9] and GHPMNs [10]) on ECL efficiency were studied systematically. The MPs were used as additives to the sample solution (0.1 mM Ru(bpy) 3 2 + ).…”

Graphene-Paper Based Electrochemical Sensors

“…Moreover, highly porous Fe 3 O 4 nanocrystal clusters were added to poly(sodium 4-styrenesulphonate) hybrid graphene paper for further enhancing the specific ability of graphene paper. This type of graphene paper-based sensors showed a high performance to detect those specific compounds containing tertiary amino groups and DNA with guanine and adenine [92,124].…”