Alkaline N-GQDs fluorescent probe for the ultrasensitive detection of creatinine

Abstract

Creatinine (Crn) is an important excretory product of the human body. Medical laboratory technology has improved over years and brought many advancements in clinical diagnostics equipment, and testing techniques and made the tests more efficient. Yet, the quantitative analysis of Crn is still carried out by the classical Jaffe’s reaction (using Picric acid (PA) with NaOH) method. Since PA is hazardous to human health, alternative solutions such as; nanoparticles and surface-modified nanoparticles can be used. Exploring the optoelectronic properties of carbon-based quantum dots for biomolecule sensing is of current interest among researchers. Nitrogen functionalized graphene quantum dots (Alk-NGQDs) measured featured Crn easier and reduced the time taken for the test carried out in laboratories. The synthesized Alk-NGQDs optical, structural, morphological properties, surface and compositions are studied through XPS, HRTEM, XRD, FTIR, and spectroscopic techniques. Alk-NGQDs at alkaline conditions (pH 9.5) form a stable complex with Crn through intermolecular charge transfer (ICT). The fluorescence titration method is used to sense Crn in commercial Crn samples and human blood serum. To understand the efficacy of sensing creatinine using Alk-NGQDs, working concentration, fluorescence quantum yield, the limit of detection, and quenching constant are calculated using the Stern-Volmer plot. The emission property of Alk-NGQDs is aimed to bring an alternative to the traditional colorimetric Jaffe’s reaction.

Nitrogen‐Doped Graphene Quantum Dots as Electrochemiluminescence‐Emitting Species for Sensitive Detection of KRAS G12C Mutation via PET‐RAFT**

“…The binding energy located at 287 and 288 eV, representing the C−O and O−C=O type bonds, respectively. In order to further determine the surface structure and composition of the NGQDs, the prepared NGQDs were analyzed by Fourier transform infrared (FTIR) spectroscopy [21] . From the Figure 3(C), the strong broad peaks at 3400 cm −1 were ascribed to the stretching vibrations of N−H and O−H; Peak at 2700 cm −1 were the characteristic absorption of the C−H stretching vibrations of saturated methyl or methylene; The two absorption peaks displayed at 1700 cm −1 and 1400 cm −1 , which were assigned to the C=O/C=C stretching vibration and C−N bending vibration absorption bands, respectively; the stretching vibration peak of C−O single bond also appeared at 1100 cm −1 .…”

“…As shown in Figure 2 In order to further determine the surface structure and composition of the NGQDs, the prepared NGQDs were analyzed by Fourier transform infrared (FTIR) spectroscopy. [21] From the Figure 3(C), the strong broad peaks at 3400 cm À 1 were ascribed to the stretching vibrations of NÀ H and OÀ H; Peak at 2700 cm À 1 were the characteristic absorption of the CÀ H stretching vibrations of saturated methyl or methylene; The two absorption peaks displayed at 1700 cm À 1 and 1400 cm À 1 , which were assigned to the C=O/C=C stretching vibration and CÀ N bending vibration absorption bands, respectively; the stretching vibration peak of CÀ O single bond also appeared at 1100 cm À 1 . Therefore, the appearance of these characteristic peaks suggested that the surface of the NGQDs were rich in carboxyl and amino functional groups, and the FTIR results were consistent with the above XPS test results.…”

Amine‐ and Polyethylene glycol‐Functionalized Pyrediyne Quantum Dots for Bioimaging Applications

“…Surface functionalization using organic moieties is reported to be an efficient method to enhance the PL (photoluminescence) properties of 2D material‐derived quantum dots. According to the literature reports, graphene quantum dots (GQDs) were widely functionalized using many polymers like polyaniline, polypyrene, polyethyleneglycols (PEGs), drugs such as folic acid, dopamine and dyes such as rhodamine and methylene blue [18–24] . Research in this area has indicated that the presence of functional groups such as carboxylic acids and epoxides can induce non‐radiative recombination centers of electron‐hole pair and thereby reducing the PL properties.…”

Aggregation-induced emission enhancement N, S-CQDs for selective detection of CIP in the environment

“…Many mechanisms have been proposed to explain more precisely how the interaction between CQDs and analytes leads to changes in the fluorescence of CQDs [12,13]. Such as photo-induced electron transfer [14], internal filtering effect [15], fluorescence resonance energy transfer (FRET) [16], aggregation-induced burst (ACQ) [17], intermolecular charge transfer (ICT) [18] and aggregation-induced emission (AIEE) [19]. Fluorescence enhancement probes are usually more advantageous than fluorescence quenching because of their higher selectivity and fewer false-positive signals [20].…”