High-Performance Non-Enzymatic Electrochemical Dopamine Sensors Based on Metal-Organic Framework Derived Co-C-Matrix Nanoplatforms

Abstract

A facile electrochemical sensing nanoplatform for detection of ultralow dopamine (DA) concentrations is developed through modification of cobalt-benzene tricarboxylic acid (Co-BTC) derived cobalt-carbon-matrix (Co-C-matrix). To enhance surface reactions and enzyme-like activities involved in interaction with DA, the structural integration of hybrid Co-C-matrix into Co-BTC as metal-organic framework is investigated, resulting in nanostructured transducing media with high sensitivity and selectivity as the catalyst. The Co-C-matrix nanoplatform exhibited the improved performance based on electrocatalytic oxidation of DA with high sensitivity of 7176 µA mM-1 cm-2 and low detection limit of 10 nM. Furthermore, the linearity of an amperometry peak toward DA concentration over a wide concentration range of 10-25 µM was observed under optimal conditions. Excellent selectivity in the presence of potential interferents and operational stability in ambient air for 30 days as well as under environmental conditions for the electrochemical oxidation of dopamine were achieved. The practical feasibility of these non-enzymatic biosensors is demonstrated on real samples, where DA is detected in human serum with outstanding recovery of up to 100%. The synergetic effect of Co atoms dispersed in the matrix of the carbon nanohybrid results in abundant active sites for DA oxidation and electron transfer pathways.

Heterophase-Structured Cobalt Hydroxide on Partly Reduced Graphene Oxide for Enhanced Dopamine Biosensing

“…Combined with the results of the structural/electronic characterization and electrochemical properties, the excellent performances of DA detection can be concluded as the following points: (i) the partially rGO can not only provide excellent electron/charge transport capacity but also increase the number of catalytic active sites on the surface of Co­(OH) 2 /PRGO, which will enhance the range of DA detection; , moreover, the open-layer structure of Co­(OH) 2 will provide larger surface areas and abundant exposed active sites toward DA detection, which will also extend the lower detection limit of DA; − , what is more, the hetero-phase structure will also introduce additional catalytic active sites to obtain excellent sensitivity of the detection and accelerate the transport of electron/charge on the electrodes for obvious detection signals; moreover, the exposed cobalt atoms will also provide excellent catalytic active sites toward DA detection, which can enhance the sensitivity and repeatability of Co­(OH) 2 /PRGO/CC in the electrochemical detection. , …”

“…Then, scanning electron microscopy (SEM) is employed to investigate the changes in the different status (powder, high-dispersed suspension, and formed electrodes) of materials. The Co(OH) 2 /PRGO can be dispersed from reunion (powder, Figure S3C,D Combined with all the structural and electronic characterizations, the Co(OH) 2 /PRGO would be endowed with many excellent performances: the accelerated translate rate of electron/charge, and the increased number of catalytic activity sites (partially rGO), 2,6 abundant exposed/selective active sites [open layer-like structure of Co(OH) 2 ]; 19,33 abundant catalytic sites (crystal defects in the interface of hetero-phase structures); 32 and the rapidly transfer/separate rates of electron/proton (synergistic effects of the hetero-phase structure). 32 Based on the above synergistic effects of the structural characterizations, Co(OH) 2 /PRGO would be endowed with an outstanding performance toward DA detection.…”

“…According to the above equations, the sensitivity of the electrodes can be calculated as 523.7 μA μM −1 cm −2 (HSG/CC) and 110.8 μA μM −1 cm −2 [Co(OH) 2 /PRGO/CC], respectively. 33,34 Meanwhile, the limit of detection (LOD) of HSG/ CC and Co(OH) 2 /PRGO/CC toward DA oxidation can be, respectively, determined as 0.29 and 0.078 nM (S/N = 3) by eq S7 and Figure S5. 28,55 According to the above results, Co(OH) 2 /PRGO/CC has a smaller detection limit and stable response signals toward blank sample compare with HSG/CC.…”

“…In this paper, we successfully prepared a mixed-phase Co­(OH) 2 [α-/β-Co­(OH) 2 ] in situ formed on the partly rGO surface [Co­(OH) 2 /PRGO] by a co-precipitation method. In this system, the hetero-phase structure [α-/β-Co­(OH) 2 ] can provide rich defects to increase active sites on the phase interfaces and accelerate the electron transfer rates by synergistic effects; the oxygen-containing functional groups of GO are utilized to increase active sites for DA detection and improve the dispersion of Co­(OH) 2 to enlarge the electrochemical active areas; the GO are partly reduced rGO by the reductive cobalt ions and 2-methylimidazole, which would increase the electronic transmission capability; the exposed cobalt atoms would also enhance the sensitive and repeatable ability of the Co­(OH) 2 /PRGO supported on carbon cloth (CC) toward DA detection. , Resultantly, Co­(OH) 2 /PRGO/CC exhibits an excellent electrochemical sensing performance, the multi-section continuous detection range (0.1 nM to 450 μM), the ultra-low detection limit (0.078 nM) and the stronger anti-interference ability, along with multidirectional practical detection capability with a high reliability in serum and pork meat.…”

Trends on the Development of Non-Enzymatic Electrochemical Sensors Modified with Metal-Organic Frameworks for the Quantification of Glucose

“…According to the literature, 73 glucose in an aqueous solution can be easily oxidized on the electrode's surface modified with MOF; 74 and the construction of these non-enzymatic sensors is easy, low cost, and presents selectivity to glucose in the presence of several interferences. The electrochemical oxidation of glucose using MOF involves two stages: at first, the metal (M) oxidation present in the MOF favored by the alkaline medium is carried out, and in the second stage, the oxidized metallic species (M*) interacts with glucose causing its oxidation to gluconolactone where two electrons and two protons are involved oxidation of glucose (Fig.…”