Plasma colorimetric aptasensor for the detection of chloramphenicol in honey based on cage Au@AuNPs and cascade hybridization chain reaction

Colorimetric aptasensor based on magnetic beads and gold nanoparticles for detecting mucin 1

In this work, a colorimetric aptasensor based on magnetic beads (MBs), gold nanoparticles (AuNPs) and Horseradish Peroxidase (HRP) was prepared for the detection of mucin 1 (MUC1). Complementary DNA of the MUC1 aptamer (Apt) immobilized on the MBs was combined with the prepared AuNPs-Apt-HRP complex (AuNPs@Apt-HRP). In the presence of MUC1, it specifically bound to Apt, resulting in the detachment of gold nanoparticles from the MBs. After magnetic separation, AuNPs@Apt-HRP was separated into the supernatant and reacted with 3,3',5,5'-Tetramethylbenzidine (TMB) to produce color reaction from colorless to blue. The linear range of MUC1 was from 75 to 500 μg/mL (R2 = 0.9878), and the detection limit was 41.95 μg/mL. The recovery rate of MUC1 in human serum was 99.18 %∼101.15 %. This method is simple and convenient. Moreover, it does not require complex and expensive equipment for detection of MUC1. It provides value for the development of MUC1 colorimetric sensors and a promising strategy for the determination of MUC1 in clinical diagnosis.

Emerging contaminants: A One Health perspective

Environmental pollution is escalating due to rapid global development that often prioritizes human needs over planetary health. Despite global efforts to mitigate legacy pollutants, the continuous introduction of new substances remains a major threat to both people and the planet. In response, global initiatives are focusing on risk assessment and regulation of emerging contaminants, as demonstrated by the ongoing efforts to establish the UN's Intergovernmental Science-Policy Panel on Chemicals, Waste, and Pollution Prevention. This review identifies the sources and impacts of emerging contaminants on planetary health, emphasizing the importance of adopting a One Health approach. Strategies for monitoring and addressing these pollutants are discussed, underscoring the need for robust and socially equitable environmental policies at both regional and international levels. Urgent actions are needed to transition toward sustainable pollution management practices to safeguard our planet for future generations.

Smartphone-integrated tri-color fluorescence sensing platform based on acid-sensitive fluorescence imprinted polymers for dual-mode visual intelligent detection of ibuprofen, chloramphenicol and florfenicol

The abuse of multiple antibiotics and anti-inflammatory drugs can harm the ecological environment and human health. Herein, a smartphone-integrated tri-color fluorescence sensing platform based on acid-sensitive fluorescence imprinted polymers was proposed for dual-mode visual intelligent detection of ibuprofen (IP), chloramphenicol (CAP), and florfenicol (FF). In this research, the dual-mode of tri-color ratiometric fluorescence imprinted sensor (TC-FMIPs) was realized at different pH environments for the detection IP, CAP, and FF. The fluorescence peak at 551 nm of TC-FMIPs was quenched in the presence of IP solution and fluorescence peak at 687 nm was quenched in the presence of CAP phosphate buffer solution (PBS, pH 7.0), while the fluorescence peak at 433 nm kept stable. Interestingly, the TC-FMIPs has a peroxidase-like activity, in which a new fluorescence peak at 561 nm was quenched and the fluorescence peak at 433 nm increased gradually with the addition of FF solution in pH 4.0 PBS. The TC-FMIPs showed a low detection limit of 10 pM, 8.5 pM, and 5.5 nM for IP, CAP, and FF, respectively. Additionally, a smartphone was used to capture of fluorescence colors and read out the RGB values for intelligent detection of IP, CAP, and FF, in which the detection limit was calculated as 15 pM, 12 pM and 7 nM toward IP, CAP and FF, respectively. The smartphone-integrated tri-color fluorescence sensing platform was developed for dual-mode visual intelligent detection of IP, CAP and FF successfully, which provided a new strategy for multi-target detection in the complex environment.

A graphene-oxide-based aptasensor for fluorometric determination of chloramphenicol in milk and honey samples utilizing exonuclease III-assisted target recycling and Nb.BbvCI-powered DNA walker cascade amplification

Herein, a graphene oxide (GO)-based fluorescence aptasensor was developed for the sensitive and selective detection of chloramphenicol (CAP), based on exonuclease III (Exo III)-assisted target recycling and Nb.BbvCI-driven DNA walker cascade amplification. Interactions between CAP, hairpin1(HP1), hairpin2 (HP2), and 3'-amino modified hairpin3 (HP3) labeled with carboxyfluorescein (FAM) and covalently coupled to GO enabled efficient CAP detection. CAP was quantitatively assayed by measuring fluorescence at excitation/emission wavelengths of 480/514 nm, resulting from the accumulation of released FAM. A good linear range of 1 fM to 1 nM and a limit of detection (LOD) of 0.875 fM (signal-to-noise (S/N)= 3) were achieved. This aptasensor can distinguish the CAP from interference antibiotics with good specificity and selectivity, even if the concentration of the interfering substance is ten-fold higher than the target concentration. Moreover, the developed fluorescence aptasensor was successfully applied for the detection of CAP in spiked milk and honey samples. Thus, this method is potentially applicable for assaying CAP in foods and provides a promising strategy for the development of fluorescence aptasensors for environmental sample analysis.

Cu Nanoparticle-Decorated Boron-Carbon-Nitrogen Nanosheets for Electrochemical Determination of Chloramphenicol

In the present work, irregular Cu nanoparticle-decorated boron-carbon-nitrogen (Cu-BCN) nanosheets were successfully synthesized. A Cu-BCN dispersion was deposited on a bare glassy carbon electrode (GCE) to prepare an electrochemical sensor (Cu-BCN/GCE) for the detection of chloramphenicol (CAP) in the environment. Cu-BCN was characterized using high-resolution scanning transmission electron microscopy (HRSTEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis, and X-ray photoelectron spectroscopy (XPS). The performance of the Cu-BCN/GCE was studied using electrochemical impedance spectroscopy (EIS), and its advantages were proven by electrode comparison. Differential pulse voltammetry (DPV) was used to optimize the experimental conditions, including the amount of Cu-BCN deposited, enrichment potential, deposition time, and pH of the electrolyte. A linear relationship between the CAP concentration and current response was obtained under the optimized experimental conditions, with a wide linear range and a limit of detection (LOD) of 2.41 nmol/L. Cu-BCN/GCE exhibited high stability, reproducibility, and repeatability. In the presence of various organic and inorganic species, the influence of the Cu-BCN-based sensor on the current response of CAP was less than 5%. Notably, the prepared sensor exhibited excellent performance in real-water samples, with satisfactory recovery.