Fabrication of a sensitive amperometric sensor for NADH and H2O2 using palladium nanoparticles-multiwalled carbon nanotube nanohybrid

Metal Nanocomposites Based Electrochemical Sensor Platform for few Emerging Biomarkers

:

Design of high-performance electrochemical sensor and biosensor platforms has attracted much devotion for the sensitive and selective detection of emergent biomarkers. Electrochemical sensor offers numerous advantageous features include cost-effective and ease of miniaturization, rapid and online monitoring, simultaneous detection ability, etc., which have captivated the potential interdisciplinary research. In this review, the advances and challenges towards the electrochemical detection of emergent biomarkers such as hydrogen peroxide, nitric oxide, β-nicotinamide adenine acetaminophen, dinucleotide (NADH) in biofluids are highlighted based on the recent research outcomes. In fact, the effective utility and benefits of transition metal nanocomposites without the utilization of biological materials, including enzymes, antibodies, etc. as electrode materials towards the detection of selected biomarkers in practical biofluids, monitoring early-stage and diagnosis of disease related biomarkers, are also described. These promising metal nanomaterials based electrochemical sensor platforms concrete the tactic for a new generation of sensing devices.

A boronic acid carbon nanodots/poly(thionine) sensing platform for the accurate and reliable detection of NADH

In this work, a novel electrochemical sensing platform was designed and fabricated by the modification of boronic acid functionalized carbon nanodots (B-CNDs) and poly(thionine) (pTHI) on an electrode surface. B-CNDs can not only accelerate electron transfer but also covalently interact with cis-diol groups of dihydronicotinamide adenine dinucleotide (NADH) through functionalized boronic acid groups. Meanwhile, pTHI served as an inner reference element to provide a built-in correction, which enabled the sensor to detect NADH with high accuracy and reliability based on a ratiometric signal (∆I_NADH/∆I_THI). The electrochemical experimental results demonstrated that the ratiometric strategy-based sensor possessed good selectivity and high sensitivity. A linear range of 5.0 × 10^-7 - 2.0 × 10^-4 mol/L for NADH detection was obtained with a limit of detection of 1.5 × 10^-7 mol/L. The sensor has been applied to analyze NADH in human serum samples with satisfactory results. The simple and effective ratiometric strategy reported here can be further used to prepare electrochemical sensors for selective, sensitive, and reliable detection of other cis-diol compounds.

Simple aminophenol-based electrochemical probes for non-enzymatic, dual amperometric detection of NADH and hydrogen peroxide

Non enzymatic detection of NADH and H₂O₂ is of practical significance for both environmental and biological prospective. However, there is no simple, straight forward electrochemical sensor available for sensing of them in real samples. Addressing this challenge, we report a simple stimuli responsive aminophenol, pre-anodized screen printed carbon electrode (SPCE*/AP) based electrochemical probes for dual detection of NADH and H₂O₂. Aminophenol prepared and adsorbed on the electrode from aminophenylboronic acid via boronic acid deprotection with H₂O₂. The SPCE*/AP fabricated with this process was characterized by cyclic voltammetry (CV), scanning electron microscope (SEM), Raman spectroscopy, UV-visible spectroscopy, and X-ray photoelectron spectroscopy (XPS). Amperometric detection results showed that SPCE*/AP electrodes exhibited linearity from 50 µM to 500 µM and from 200 µM to 2 mM with a detection limit (S/N = 3) of 4.2 µM and 28.9 µM for NADH and H₂O₂, respectively. Excellent reproducibility and selectivity for NADH and H₂O₂ were observed for this electrochemical platform. In addition, the matrix effect was investigated further using the same technique to analyze NADH and H₂O₂ in human urine samples, human serum samples, cell culture medium (containing 10% fetal bovine serum, FBS), and environmental water samples (tap water and rain water). Also, the present sensor demonstrated promising outcomes with living cells (normal cells and cancer cells).

Highly sensitive amperometric biosensor for determination of NADH and ethanol based on Au-Ag nanoparticles/poly(L-Cysteine)/reduced graphene oxide nanocomposite

This work presents the fabrication of a novel nicotinamide adenine dinucleotide (NADH) sensor using gold-silver bimetallic nanoparticles (Au-AgNPs), poly(L-Cysteine) (P(L-Cys)) and electrochemically reduced graphene oxide (ERGO) modified glassy carbon electrode (GCE/Au-AgNPs/P(L-Cys)-ERGO). The composite electrode exhibited an excellent electrocatalytic response towards NADH at a low oxidation potential (+ 0.35V) and minimization of surface contamination due to the synergistic effects of the Au-AgNPs, polymer and ERGO. Under optimum conditions, modified sensors allowed the detection of NADH with a wide linear range from 0.083µM to 1.05mM with a low detection limit of 9.0nM (S/N = 3). Moreover, this modified electrode was also used as a sensitive ethanol biosensor, which was prepared with alcohol dehydrogenase (ADH) via glutaraldehyde, bovin serum albumin and nafion (Naf). There was a linear response for ethanol in the concentration range from 0.017 to 1.845mM with a low detection limit of 5.0µM (S/N = 3). The GCE/Au-AgNPs/P(L-Cys)-ERGO/ADH/Naf electrode can be successfully used for the determination of ethanol in different commercial beverages.