Porous Nitrogen-Doped Crumpled Graphene Nanoparticles: A Metal-Free Nanozyme for Selective Detection of Dopamine in Aqueous Medium and Human Serum

Abstract

Accurate detection of trace analytes in biological samples is essential for medical diagnostics but usually requires complex and expensive instruments. Nanozymes, a series of nanosized systems with a catalytic activity mimicking that of peroxidase enzymes, offer a useful alternative for the design of sensing devices. In this article, we describe the synthesis of porous 3D nitrogen-doped crumpled graphene nanoparticles (CGNPs) and their use as a platform for the sensitive detection of dopamine (DA) in complex biological media such as blood serum. CGNPs were prepared by doping graphene oxide (GO) using ammonium hydroxide in a hydrothermal treatment. This procedure leads to the crumpling of GO sheets into porous sphere-like nanoparticles, with a diameter of 34 ± 10 nm. These nanoparticles with high surface area and improved electronic properties proved very active for the oxidation of the peroxidase substrate 3,3′,5,5′-tetramethylbenzidine (TMB). Our sensing device relied on the scavenging of hydroxyl radicals by DA, resulting in a turn-off effect for TMB oxidation. The system selectively detected DA with a limit of detection of 1.15 μM and a linearity range of 1 to 20 μM. The system also possessed good selectivity for DA in the presence of various interfering species, as well as in human blood serum.

Polyaniline–Graphene Oxide Composites Decorated with ZrO2 Nanoparticles for Use in Screen-Printed Electrodes for Real-Time l-Tyrosine Sensing

“…This will simplify the process economically and ensure that the material produced has real-world applications. Various real-time sensors are available nowadays for different types of biomolecules like dopamine, glutamic acid, serotonin, glucose, cortisol, etc. One of the important amino acid biomarkers is l -Tyrosine ( l -Tyr), which is a naturally occurring aromatic amino acid that regulates protein synthesis, maintains a positive nitrogen balance, and functions as a singlet oxygen quencher in the human body …”

Smart-Phone-Assisted Optical Biosensors Based on Silk-Fibroin-Decorated Reduced Graphene Oxide Quantum Dots for Fluorescent Turn-On Recognition of l-Dopa

“…36 Similarly, Boruah et al used human blood serum as sensing media for the detection of dopamine using nitrogen-doped GO. 37 Aggregation-induced-emission (AIE) or aggregation-induced emission enhancement (AIEE) is one of the well-known mechanistic pathways responsible for the fluorescence enhancement of fluorophore units in their aggregated states. In a non-aggregated state, molecules undergo intramolecular motions (vibration and rotation) against their molecular axis that serves as a relaxation pathway for excited-state molecules to decay.…”

“…Real-time monitoring of key biomolecules in the human body is vital in terms of biomedical applications where a variety of biosensing media, including blood serum, urine samples, sweat samples, cells from various organs, pharmaceutical tablets, etc. , Recently, Li et al used Pt/MXene-based flexible wearable sensors for the detection of glucose in sweat and Buledi et al fabricated reusable nickel oxide/graphene oxide (GO)-based electrochemical sensors for the detection of linezolid drug in urine samples . Similarly, Boruah et al used human blood serum as sensing media for the detection of dopamine using nitrogen-doped GO …”

Enhancing electrochemical sensing through the use of functionalized graphene composites as nanozymes

“…[6][7][8][9][10] The up-to-the-minute artificial enzymes are nanozymes, and they can be separated into four groups matching the type of material: metallic nanozymes (e.g., silver, copper, gold, etc. ), [11][12][13] metal-oxide nanozymes (e.g., cerium or ferric oxide), carbon-related nanozymes (e.g., functionalized graphene or graphene quantum dots) [14][15][16][17] and other 2D nanomaterials. 5,18,19 These nanozymes were described as oxidoreductase-mimicking materials (e.g., laccase, horseradish peroxidase), hydrolases, and lyases such as phosphatase or anhydrase, respectively.…”