A sensitive electrochemiluminescence glucose biosensor based on graphene quantum dot prepared from graphene oxide sheets and hydrogen peroxide

Advancement in Nanoparticle-Based Biosensors for Point-of-Care In Vitro Diagnostics

Abstract:

Recently, there has been great progress in the field of extremely sensitive and precise detection of bioanalytes. The importance of the utilization of nanoparticles in biosensors has been recognized due to their unique properties. Specifically, nanoparticles of gold, silver, and magnetic plus graphene, quantum dots, and nanotubes of carbon are being keenly considered for utilizations within biosensors to detect nucleic acids, glucose, or pathogens (bacteria as well as a virus). Taking advantage of nanoparticles, faster and sensitive biosensors can be developed. Here we review the nanoparticles' contribution to the biosensors field and their potential applications.

Recent Progress in Nanobiosensors for Precise Detection of Blood Glucose Level

Diabetes mellitus (DM) follows a series of metabolic diseases categorized by high blood sugar levels. Owing to the increasing diabetes disease in the world, early diagnosis of this disease is critical. New methods such as nanotechnology have made significant progress in many areas of medical science and physiology. Nanobiosensors are very sensible and can identify single virus particles or even low concentrations of a material that can be inherently harmful. One of the main factors for developing glucose sensors in the body is the diagnosis of hypoglycemia in individuals with insulin-dependent diabetes. Therefore, this study aimed to evaluate the most up-to-date and fastest glucose detection method by nanosensors and, as a result, faster and better treatment in medical sciences. In this review, we try to explore new ways to control blood glucose levels and treat diabetes. We begin with a definition of biosensors and their classification and basis, and then we examine the latest biosensors in glucose detection and new biosensors applications, including the artificial pancreas and updating quantum graphene data.

Green sonochemistry assisted synthesis of hollow magnetic and photoluminescent MgFe2O4-carbon dot nanocomposite as a sensor for toxic Ni(ii), Cd(ii) and Hg(ii) ions and bacteria

The purpose of this study was synthesis of photoluminescent nanoparticles for detection of toxic metal ions. Also, these controllable magnetic nanocomposites were used for detection of Pseudomonas aeruginosa bacteria. Carbon nano-templates were formed by calcination and sonication of lemon extract as a bio-compatible precursor. Then MgFe₂O₄ nanoparticles were incorporated on the carbon nano-templates. The composite was calcinated to decompose carbon and obtain hollow structures. Finally, photoluminescent carbon dots were deposited on the porous magnesium ferrite core. Because of the hollow structure, carbon dots can diffuse to the Mg-ferrite core so magnetic and photoluminescence properties are available simultaneously. Photoluminescence intensity decreases with increasing Ni(ii), Cd(ii), Hg(ii) metal ions and Pseudomonas aeruginosa. Results show an effective nanostructure for identification of toxic metal ions and also bacteria.

The purpose of this study is synthesis of magnetic and photoluminescence nanoparticles at the same time for finding of bacteria that could be fatal and its detection are crucial for some illness prohibition.

Optical glucose biosensor built-in disposable strips and wearable electronic devices

On-demand screening, real-time monitoring and rapid diagnosis of ubiquitous diseases, such as diabetes, at early stages are indispensable in personalised treatment. Emerging impacts of nano/microscale materials on optical and portable biosensor strips and devices have become increasingly important in the remarkable development of sensitive visualisation (i.e. visible inspection by the human eye) assays, low-cost analyses and personalised home testing of patients with diabetes. With the increasing public attention regarding the self-monitoring of diabetes, the development of visual readout, easy-to-use and wearable biosensors has gained considerable interest. Our comprehensive review bridges the practical assessment gap between optical bio-visualisation assays, disposable test strips, sensor array designs and full integration into flexible skin-based or contact lens devices with the on-site wireless signal transmission of glucose detection in physiological fluids. To date, the fully modulated integration of nano/microscale optical biosensors into wearable electronic devices, such as smartphones, is critical to prolong periods of indoor and outdoor clinical diagnostics. Focus should be given to the improvements of invasive, wireless and portable sensing technologies to improve the applicability and reliability of screen display, continuous monitoring, dynamic data visualisation, online acquisition and self and in-home healthcare management of patients with diabetes.

Developing an integrated microfluidic and miniaturized electrochemical biosensor for point of care determination of glucose in human plasma samples

A cost-effective, point of care (POC) device based on highly oriented CNT arrays was developed as an electrochemical assay for real-time and sensitive detection of glucose in complex samples. A low-cost, microcontroller-based potentiostat consisting of Arduino Due and LMP9100-EVM was developed to perform electrochemical measurements such as cyclic voltammetry (CV) and amperometry. A syringe pump based on open-source electronics was designed to direct the flow through a microfluidic chip. Vertically aligned carbon nanotube (VACNT) sensor arrays, in combination with the miniature potentiostat and the syringe pumps, were utilized as a POC device for the rapid and accurate detection of glucose. The structure and morphology of samples were characterized by field emission scanning electron microscopy (FESEM) and attenuated total reflectance Fourier transform infrared spectrometry (ATR-FTIR). CV as well as electrochemical impedance spectroscopy (EIS) was performed to investigate the electrochemical behavior of the electrode with respect to different diffusion regimes. The mediator-less biosensor had a limit of detection of 23 μM and sensitivity of 1462 μA mM^-1 cm^-2 and 1050 μA mM^-1 cm^-2 at the linear range of 1.2-7.8 mM and 7.8-11.2 mM, respectively. The presence of other biological compounds such as uric acid (UA) and ascorbic acid (AA) did not interfere with the detection of glucose. Finally, the designed POC device was successfully applied for the determination of glucose in human blood plasma samples.

Applications of Graphene Quantum Dots in Biomedical Sensors

Due to the proliferative cancer rates, cardiovascular diseases, neurodegenerative disorders, autoimmune diseases and a plethora of infections across the globe, it is essential to introduce strategies that can rapidly and specifically detect the ultralow concentrations of relevant biomarkers, pathogens, toxins and pharmaceuticals in biological matrices. Considering these pathophysiologies, various research works have become necessary to fabricate biosensors for their early diagnosis and treatment, using nanomaterials like quantum dots (QDs). These nanomaterials effectively ameliorate the sensor performance with respect to their reproducibility, selectivity as well as sensitivity. In particular, graphene quantum dots (GQDs), which are ideally graphene fragments of nanometer size, constitute discrete features such as acting as attractive fluorophores and excellent electro-catalysts owing to their photo-stability, water-solubility, biocompatibility, non-toxicity and lucrativeness that make them favorable candidates for a wide range of novel biomedical applications. Herein, we reviewed about 300 biomedical studies reported over the last five years which entail the state of art as well as some pioneering ideas with respect to the prominent role of GQDs, especially in the development of optical, electrochemical and photoelectrochemical biosensors. Additionally, we outline the ideal properties of GQDs, their eclectic methods of synthesis, and the general principle behind several biosensing techniques.

Graphene quantum dot electrochemiluminescence increase by bio-generated H2O2 and its application in direct biosensing

In this study, a novel signal-increase electrochemiluminescence (ECL) biosensor has been developed for the detection of glucose based on graphene quantum dot/glucose oxidase (GQD/GOx) on Ti foil. The proposed GQD with excellent ECL ability is synthesized through a green one-step strategy by the electrochemical reduction of graphene oxide quantum dot. Upon the addition of glucose, GOx can catalytically oxidize glucose and the direct electron transfer between the redox centre of GOx and the modified electrode also has been realized, which results in the bio-generated H₂O₂ for ECL signal increase in GQD and realizes the direct ECL detection of glucose. The signal-increase ECL biosensor enables glucose detection with high sensitivity reaching 5 × 10^-6 mol l^-1 in a wide linear range from 5 × 10^-6 to 1.5 × 10^-3 mol l^-1. Additionally, the fabrication process of such GQD-based ECL biosensor is also suitable to other biologically produced H₂O₂ system, suggesting the possible applications in the sensitive detection of other biologically important targets (e.g. small molecules, protein, DNA and so on).

Detección electroquímica de peróxido de hidrógeno usando peroxidasa de pasto Guinea (Panicum maximum) inmovilizada sobre electrodos serigrafiados de puntos cuánticos

Los biosensores electroquímicos son herramientas analíticas de rápida y confiable respuesta que han adquirido especial interés en los últimos años gracias a la posibilidad de integrar biomoléculas con electrodos hechos a base de materiales nanométricos. En este trabajo se desarrolló un biosensor electroquímico para detección de peróxido de hidrógeno (H2O2) usando peroxidasa de pasto Guinea (PPG) inmovilizada sobre electrodos serigrafiados de puntos cuánticos (ESPC). La PPG fue aislada y parcialmente purificada a partir de hojas de pasto Guinea con una actividad específica de 602 U mg-1. Posteriormente, la PPG fue inmovilizada sobre la superficie del ESPC mediante adsorción física y el estudio del comportamiento electroquímico fue llevado a cabo mediante voltamperometría cíclica y cronoamperometría. La PPG reveló una pareja bien definida de señales redox a 17 mV/-141 mV correspondientes al proceso redox del grupo hemo (Fe2+/Fe3+) de las peroxidasas. La reducción bioelectrocatalítica del peróxido de hidrógeno se observó a un potencial redox de -645 mV vs Ag. Este proceso fue controlado por difusión de las especies en la superficie del electrodo en un rango de velocidad de barrido lineal de 50-500 mV/s. La cronoamperometría permitió la construcción de curvas de calibración entre la corriente de reducción y la concentración del H2O2 para la determinación de parámetros analíticos como sensibilidad, rango lineal y nivel mínimo de detección. El desarrollo de este biosensor amperométrico se convierte en un paso preliminar para la construcción de un dispositivo portátil y de respuesta rápida para el análisis de H2O2 en muestras de interés ambiental y biomédico.

Review of Carbon and Graphene Quantum Dots for Sensing

Carbon and graphene quantum dots (CQDs and GQDs), known as zero-dimensional (0D) nanomaterials, have been attracting increasing attention in sensing and bioimaging. Their unique electronic, fluorescent, photoluminescent, chemiluminescent, and electrochemiluminescent properties are what gives them potential in sensing. In this Review, we summarize the basic knowledge on CQDs and GQDs before focusing on their application to sensing thus far followed by a discussion of future directions for research into CQDs- and GQD-based nanomaterials in sensing. With regard to the latter, the authors suggest that with the potential of these nanomaterials in sensing more research is needed on understanding their optical properties and why the synthetic methods influence their properties so much, into methods of surface functionalization that provide greater selectivity in sensing and into new sensing concepts that utilize the virtues of these nanomaterials to give us new or better sensors that could not be achieved in other ways.

Nitrogen-doped graphene quantum dots coated with gold nanoparticles for electrochemiluminescent glucose detection using enzymatically generated hydrogen peroxide as a quencher

Nitrogen-doped graphene quantum dots (N-GQDs) were prepared from dicyandiamide and then used as both an electrochemiluminescence (ECL) emitter and a reductant to produce gold nanoparticles (Au-N-GQDs) on their surface without using any reagent. In order to avoid resonance energy transfer, the Au-N-GQDs were stabilized with chitosan. Transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), UV-vis spectroscopy (UV-vis) and ECL methods were used to characterize the nanocomposite. The materials was placed on a glassy carbon electrode (GCE), and the ECL signals are found to be strongly quenched by hydrogen peroxide that is enzymatically produced by oxidation of glucose. With the applied typical potential of -1.7 V, the ECL of the Au-N-GQDs modified GCE decreases linearly in the 10 nM to 5.0 μM glucose concentration range, and the lower detection limit is 3.3 nM. The influence of H₂O₂ to the signal has been discussed and a possible mechanism has been presented. Graphical abstract Schematic presentation of the reduction of gold nanoparticles with nitrogen-droped graphene quantum dots (N-GQDs) to form Au-N-GQDs. They were used to detect glucose by electrochemiluminescence through a signal off strategy.