Sodium pyrophosphate

Loop-mediated isothermal amplification (LAMP) is a rapid and sensitive approach for foodborne pathogen detection; however, a simple, user-friendly, and naked-eye readable readout method remains a challenge. Herein, we synthesized bovine serum albumin stabilized gold nanoclusters (BSA-AuNCs), which exhibit fluorescence quenching upon copper ions (Cu²⁺) binding and fluorescence recovery in the presence of phosphate ions (PPi). Leveraging this property, we developed a label-free fluorescence turn-on assay for naked-eye LAMP detection by monitoring PPi accumulation under UV light. To mitigate potential cross-contamination risks inherent in LAMP workflows, we integrated the BSA-AuNCs-Cu²⁺ complex into the reaction lid, enabling a closed, one-pot detection system. This method demonstrated high sensitivity, detecting Salmonella enterica at concentrations as low as 10¹ CFU/mL within 40 min (excluding nucleic acid extraction process). With its customizable primers and naked-eye visual detection capability, this assay offers a versatile and practical tool for rapid pathogen screening in diverse applications.

A novel portable electrochemical sensor for Hg²⁺ detection was developed, featuring integration with a smartphone-based potentiostat and utilizing a β-cyclodextrin-coated porous graphene ink-modified screen-printed electrode (β-CD/P-Gi/SPE). The use of β-cyclodextrin enhances molecular recognition and selectivity for Hg²⁺, while porous graphene ink improves conductivity and sensitivity, addressing limitations of existing electrode materials. Comprehensive characterization using SEM, EDX, FT-IR, and Raman spectroscopy confirmed the successful incorporation of the β-CD polymer film onto the P-Gi. The electrochemical properties of the modified electrode were evaluated using electrochemical impedance spectroscopy and cyclic voltammetry. The adsorptive anodic stripping voltammetry (AdASV) condition was also optimized. Under optimal conditions, AdASV demonstrated that the oxidation peak current was linearly proportional to the Hg²⁺ concentration in the range of 0.50-80 μg mL^-1 with a detection limit of 0.11 μg mL^-1. Furthermore, the sensor exhibited excellent reproducibility, sustained long-term stability, and a fast current response. To demonstrate the practical applicability of the proposed sensor, the proposed sensor successfully determined Hg²⁺ in skin whitening creams.