A Label-Free Colorimetric Assay Based on Gold Nanoparticles for the Detection of H2O2 and Glucose

Microplasma-assisted construction of cross-linked network hierarchical structure of NiMoO4 nanorods @NiCo-LDH nanosheets for electrochemical sensing of non-enzymatic H2O2 in food

The accumulation of small doses of hydrogen peroxide (H2O2) into food can cause many diseases in the human body, and it is urgent to develop efficient detection methods of H2O2. Herein, the hierarchical structure composite of NiCo-LDH nanosheets crosslinked NiMoO4 nanorods was grown in situ on carbon cloth (NiMoO4 NRs@NiCo-LDH NSs/CC) by micro-plasma assisted hydrothermal method. Thanks to the synergistic effect of three metals and (NiMoO4 NRs@NiCo-LDH NSs/CC) provided by nanorods/nanosheets hierarchical structure, NiMoO4 NRs@NiCo-LDH NSs/CC exposes more active sites and achieves rapid electron transfer. The H2O2 electrochemical sensor was constructed as the working electrode with a linear range of 1 μmol L-1 to 9.0 mmol L-1 and detection limit of 112 nmol L-1. In addition, the sensor has been successfully applied to the detection of H2O2 in food samples, the recovery rate is 95.2%-106.62%, RSD < 4.89%.

Gold nanourchin on multiple-point dielectrode for glucose biosensing by current-potential measurement

Gestational diabetes (GD) is a condition characterized by elevated blood sugar levels during pregnancy. GD poses various health risks, such as serious birth injuries, the need for cesarean delivery, and the necessity of newborn care. Monitoring glucose levels is essential for ensuring safe delivery and reducing the risks to both the mother and fetus. Various sensors are readily available for monitoring glucose levels, and researchers are continually working to develop highly sensitive glucose sensors. This research aimed to develop a gold nanourchin (AuNU)-hybrid biosensor for quantifying glucose on a multi-point electrode sensor. Glucose oxidase (GOx) was attached to the AuNU and seeded on the sensing surface using an amine linker. The current-potential (1-2 V at 0.1 V sweep) was recorded for the GOx-glucose interaction, with a limit of detection of 560 μM and a regression coefficient (R2) of 0.9743 [y = 0.9106x - 0.9953] on the linear curve. The sensitivity was estimated to be 3.5 mAcm-2M-1. Furthermore, control experiments with galactose, sucrose, and fructose did not yield an increase in current-potential, confirming specific glucose detection. This experiment helps in monitoring glucose levels to manage conditions associated with GD.

A Novel Method for the Pre-Column Derivatization of Saccharides from Polygonatum cyrtonema Hua. by Integrating Lambert-Beer Law and Response Surface Methodology

Traditional Chinese medicine (TCM) safety and effectiveness can be ensured by establishing a suitable quality assessment system. This work aims to develop a pre-column derivatization HPLC method for Polygonatum cyrtonema Hua. quality control. In this study, 1-(4'-cyanophenyl)-3-methyl-5-pyrazolone (CPMP) was synthesized and reacted with monosaccharides derived from P. cyrtonema polysaccharides (PCPs), followed by HPLC separation. According to the Lambert-Beer law, CPMP has the highest molar extinction coefficient of all synthetic chemosensors. A satisfactory separation effect was obtained under a detection wavelength of 278 nm using a carbon-8 column and gradient elution over 14 min, with a flow rate of 1 mL per minute. Glucose (Glc), galactose (Gal), and mannose (Man) make up the majority of the monosaccharide components in PCPs, and their molar ratios are 1.73:0.58:1. The confirmed HPLC method has outstanding precision and accuracy, establishing a quality control method for PCPs. Additionally, the CPMP showed a visual improvement from colorless to orange after the detection of reducing sugars, allowing for further visual analysis.