Simple paper-based colorimetric and fluorescent glucose sensor using N-doped carbon dots and metal oxide hybrid structures
Graphical abstract
Introduction
Diabetes mellitus is one of a group of metabolic disorders related to glucose, which can cause multi-system damage, such as eyes, kidneys, heart, and other human organs [1]. Hence, the early detection and regular monitoring of the glucose levels in the blood are key factors in preventing the complications of diabetes. In recent years, enormous efforts have been made to determine the glucose concentration with high accuracy, such as surface-enhanced Raman scattering, electrochemical, chemiluminescence, fluorescence, and colorimetric approaches [[2], [3], [4], [5], [6], [7]]. Among these approaches, colorimetric and fluorescent methods have attracted tremendous attention owing to their simplicity, low-experimental cost, high sensitivity, portability, and recognition of color discrimination. On the other hand, many studies have been based on single signal determination (colorimetric or fluorescence). On the other hand, the single signal output could be affected by external conditions, such as operation and instrument efficiency [8,9]. Moreover, there are few colorimetric and fluorescent dual-signal sensor for glucose with an expected rapid response and feasible measurement available. Therefore, a method with dual signals to detect glucose is needed.
In a typical colorimetric method, glucose would be oxidized by glucose oxidase (GOx) to generate gluconolactone and H2O2. The concentration of glucose is then measured by assessing the change from a colorless to a colored product of the peroxidase substrate in the presence of a peroxidase catalyst [10]. Nevertheless, the use of natural enzymes as a peroxidase catalyst still has some drawbacks, including adversely affected by environmental factors and the relatively high cost. To solve this problem, it is essential to investigate proper peroxidase mimetic nanomaterials to substitute for natural enzymes. Several studies have reported that various transition metal oxides nanoparticles (NPs) [11], metal particles [10], perovskite NPs [12], and metal oxides nanocomposite with carbon materials [13,14] can catalyze the reaction through the peroxidase-catalytic activity. Recently, ferric oxide and manganese oxide have received a great interest across technological applications, including energy storage [15,16], catalyst [17], magnetism [18,19], environmental [20], sensor [21,22], drug delivery [23], owing to their outstanding structural combined with chemical and physical properties. Apart from unique properties, ferric oxide and manganese oxide have been reported to show excellent peroxidase-like activity. The use of composites of both as the enzyme peroxidase material has not been reported widely. Accordingly, a well-designed morphology and enhanced active site of the catalytic material are desired.
Among the ideal nanomaterials, carbon dots (CDs) are potential candidates for chemical sensing and bioimaging applications owing to their low cytotoxicity, good biocompatibility, superior photostability, eco-friendly, tunable fluorescence, and distinct optical properties. The introduction of an N atom to the graphitic carbon structures can enhance their electrical property and chemical stability, which leads to improved working performance towards specific target materials. Recently, CDs as well as N-doped carbon dots (NCDs) have been utilized for a range of applications, such as oxygen reduction reaction [24,25], water splitting [26,27], biosensors [28,29], batteries [30], bioimaging [31], and photocatalysts [32]. A versatile method to fabricate novel NCDs fluorescent materials used the hydrothermal process of different saccharides [33,34]. After the hydrothermal process, saccharides form carbonaceous nanomaterials, which can be functionalized further to improve the optical and fluorescent properties of the obtained carbon dots. Moreover, to enrich the potential applications, decorating other metal oxides with NCDs is an efficient way of tuning the unique electronic, catalytic, and optical properties. Thus, the introduction of NCDs to metal oxides will enhance their versatile properties further.
Along with the development of information technology, the smartphone has become more easily accessible. Recently, some proposed methods using smartphones as detectors for advanced detection applications such as colorimetric, fluorescence and electrochemiluminescence sensing were developed [[35], [36], [37], [38], [39], [40]]. This approach not only provides portable, rapid response, cost-effective diagnostic equipment but also enables on-demand analysis with reliable results. Therefore, the development of an integrated visual testing platform based on a combination of smartphone and composite material has become a great potential alternative to traditional diagnostic testing devices in analytical applications.
In this research, uric acid was used as a direct monomer source for the fabricated of NCDs along with glucose using a bottom-up method. Owing to the interaction between the aldehyde groups of glucose and the amine groups of uric acid without the assistance of a catalyst [41], it was expected that the product of the reaction would lead to N-containing carbon nanostructures. The composite with NCDs decorated on manganese oxide/ferric oxide (MFNCDs), as a new peroxidase mimetic catalyst, was fabricated using a simple one-pot hydrothermal process. The results showed that the NCDs were well dispersed over the metal oxide surface, which provided more beneficial interface active sites and enhanced the intrinsic peroxidase-like catalytic activity towards TMB in the presence of H2O2 to generate the blue color product (oxTMB). Moreover, the fluorescence of the MFNCDs/TMB system can be quenched with the presence of H2O2 owing to the inner filter effect (IFE) and electron transfer between the components in the system. Hence, with the aforementioned properties, a dual sensor based on colorimetric and fluorescent method for the quantitative determination of the concentration of H2O2 and glucose was developed. The additional advantages, including color readout on the paper-sensing device via an application (APP) integrated with a smartphone, low cytotoxicity, good biocompatibility as well as feasibility in the real samples, were outstanding characteristics for practical applications.
Section snippets
Experimental details
Detailed information on the materials and analysis apparatus is described in the supporting materials.
Synthesis and characterization of MFCNDs
Scheme 1 presents the approach for fabricating the MFCNDs. The crystallographic phase of the as-obtained samples was characterized using X-ray diffraction (XRD). As shown in Fig. S2, the XRD pattern of NCDs showed a broad peak at approximately 25.3° 2θ, which corresponded to graphitic-like carbon systems (002) (JCPDS 08–0415) [34,42]. The interlayer spacing of d002 = 0.38 nm was higher than that of the ideal graphite due to the incorporation of heteroatoms on the basal plane, which was
Conclusions
The dual signal sensor for H2O2 and glucose were developed successfully using fluorescent and colorimetric methods based on the oxidation of TMB in the presence of MFNCDs as a peroxidase mimetic catalyst. The sensing system delivered a wide detection range and a low detection limit for the detection of both H2O2 and glucose. The obtained MFNCDs-based sensor exhibited high selectivity against various common interfering species, long-term stability, excellent bio-imaging properties, and low
CRediT authorship contribution statement
Yen-Linh Thi Ngo: Methodology, Investigation, Visualization, Data curation, Writing - original draft. Phi Luan Nguyen: Methodology, Investigation, Visualization, Data curation. Jayasmita Jana: Software, Validation. Won Mook Choi: Resources, Investigation. Jin Suk Chung: Project administration. Seung Hyun Hur: Writing - review & editing, Supervision.
Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgments
This study was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by The Ministry of Science, ICT and Future Planning (2019R1A2B5B02069683).
References (62)
- et al.
A novel peroxidase mimetic Co-MOF enhanced luminol chemiluminescence and its application in glucose sensing
Sensor. Actuator. B Chem.
(2019) - et al.
Aminoboronic acid-functionalized graphitic carbon nitride quantum dots for the photoluminescence multi-chemical sensing probe
Dyes Pigments
(2019) - et al.
Highly sensitive smartphone-integrated colorimetric glucose sensor based on MnFe2O4 – graphitic carbon nitride hybrid nanostructure
Mater. Res. Bull.
(2020) - et al.
Fluorometric and colorimetric sensor array for discrimination of glucose using enzymatic-triggered dual-signal system consisting of Au@Ag nanoparticles and carbon nanodots
Sensor. Actuator. B Chem.
(2018) - et al.
A carbon dot-based ratiometric fluorometric and colorimetric method for determination of ascorbic acid and of the activity of ascorbic acid oxidase
Microchim. Acta
(2019) - et al.
Colorimetric detection of glucose based on gold nanoparticles coupled with silver nanoparticles
Spectrochim. Acta, Part A
(2017) - et al.
Novel biotemplated MnO2 1D nanozyme with controllable peroxidase-like activity and unique catalytic mechanism and its application for glucose sensing
Sensor. Actuator. B Chem.
(2017) - et al.
Colorimetric and fluorometric dual-signal determination of dopamine by the use of Cu-Mn-O microcrystals and C-dots
Sensor. Actuator. B Chem.
(2019) - et al.
B,N-carbon dots-based ratiometric fluorescent and colorimetric dual-readout sensor for H2O2 and H2O2-involved metabolites detection using ZnFe2O4 magnetic microspheres as peroxidase mimics
Sensor. Actuator. B Chem.
(2018) - et al.
Fabrication of α-Fe2O3/g-C3N4 composites for cataluminescence sensing of H2S
Sensor. Actuator. B Chem.
(2015)
One-pot synthesis of nitrogen-rich carbon dots decorated graphene oxide as metal-free electrocatalyst for oxygen reduction reaction
Carbon
Highly biocompatible phenylboronic acid-functionalized graphitic carbon nitride quantum dots for the selective glucose sensor
Sensor. Actuator. B Chem.
Carbon quantum dots from glucose oxidation as a highly competent anode material for lithium and sodium-ion batteries
Electrochim. Acta
Carbon dots, a powerful non-toxic support for bioimaging by fluorescence nanoscopy and eradication of bacteria by photothermia
Nanoscale Adv
Recent progress on the photocatalysis of carbon dots: classification, mechanism and applications
Nano Today
Graphene quantum dots prepared from glucose as optical sensor for glucose
J. Lumin.
Smartphone based platform for ratiometric fluorometric and colorimetric determination H2O2 and glucose
Sensor. Actuator. B Chem.
Point-of-care testing based on smartphone: the current state-of-the-art (2017–2018)
Biosens. Bioelectron.
Biosensors and bioelectronics on smartphone for portable biochemical detection
Biosens. Bioelectron.
Use of a mobile phone for potentiostatic control with low cost paper-based microfluidic sensors
Anal. Chim. Acta
Mobile phone-based electrochemiluminescence sensing exploiting the ‘USB On-The-Go’ protocol
Sensor. Actuator. B Chem.
Microwave assisted green synthesis of fluorescent N-doped carbon dots: cytotoxicity and bio-imaging applications
J. Photochem. Photobiol. B Biol.
Ethylenediamine-assisted hydrothermal synthesis of nitrogen-doped carbon quantum dots as fluorescent probes for sensitive biosensing and bioimaging
Sensor. Actuator. B Chem.
Growth of CuO nanoneedles on graphene quantum dots as peroxidase mimics for sensitive colorimetric detection of hydrogen peroxide and glucose
Sensor. Actuator. B Chem.
The horseradish peroxidase-catalyzed oxidation of 3,5,3’,5’-tetramethylbenzidine. Free radical and charge-transfer complex intermediates
J. Biol. Chem.
Inner filter effect-based fluorescent sensing systems: a review
Anal. Chim. Acta
Uncovering the actual inner-filter effect between highly efficient carbon dots and nitroaromatics
Spectrochim. Acta, Part A
Inner filter effect in fluorescence spectroscopy: as a problem and as a solution
J. Photoch. Photobio. C
Interfacial engineering of carbon dots with benzenediboronic acid for fluorescent biosensing
Nanoscale Adv
Diabetes mellitus and the skin
Rev. Endocr. Metab. Disord.
Electroless deposition of Pd nanostructures for multifunctional applications as surface-enhanced Raman scattering substrates and electrochemical nonenzymatic sensors
ACS Appl. Nano Mater.
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