Ferrocene-functionalized nanocomposites as signal amplification probes for electrochemical immunoassay of Salmonella typhimurium.

An electrochemical immunosensor based on ferrocene (Fc)-functionalized nanocomposites was fabricated as an efficient electroactive signal probe to amplify electrochemical signals for Salmonella typhimurium detection. The electrochemical signal amplification probe was constructed by encapsulating ferrocene into S. typhimurium-specific antimicrobial peptides Magainin I (MI)-Cu3(PO4)2 organic-inorganic nanocomposites (Fc@MI) through a one-step process. Magnetic beads (MBs) coupled with antibody were used as capture ingredient for target magnetic separation, and Fc@MI nanoparticles were used as signal labels in the immunoassays. The sandwich of MBs-target-Fc@MI assay was performed using a screen-printed carbon electrode as transducer surface. The immunosensor platform presents a low limit of detection (LOD) of 3 CFU·mL-1 and a linear range from 10 to 107 CFU·mL-1, with good specificity and precision, and was successfully applied for S. typhimurium detection in milk. Graphical abstract One-pot process antimicrobial peptides Magainin I-Cu3(PO4)2 organic-inorganic nanocomposites (Fc@MI) were used as ideal electrochemical signal label, integrating both essential functions of biological recognition and signal amplification. Screen-printed carbon electrode (SPCE) was used as the electrochemical system for Salmonella typhimurium detection.

[Tending of wild Heterosmilax yunnanensis].

To minimize the predatory harvest of Heterosmilax yunnanensis and maintain the sustainable utilization of its resources, a study on the tending technology of wild H. yunnanensis was carried out. The results showed that the tuber tending model had a higher seed emergence rate, shorter growth period and easier control of male and female ratios than other tending models; by removing shrubs, topping, bending pruning, controlling insects and pests and other effective technical measures, the growth period of H. yunnanensis was shortened; the average annual net income of the tending area was 1 086 yuan/mu (1 mu≈666.67 m²), which was 86.9% higher than before. This study was conducive to increasing the yield and quality of H. yunnanensis in Karst landform area, and instructive for the tending of other wild traditional Chinese medicinal herbs in this area.