Silica-coated phosphorescent nanoprobes for selective cell targeting and dynamic bioimaging of pathogen-host cell interactions

Molecular imprinting-based indirect fluorescence detection strategy implemented on paper chip for non-fluorescent microcystin

Fluorescence analysis is a fast and sensitive method, and has great potential application in trace detection of environmental toxins. However, many important environmental toxins are non-fluorescent substances, and it is still a challenge to construct a fluorescence detection method for non-fluorescent substances. Here, by means of charge transfer effect and smart molecular imprinting technology, we report a sensitive indirect fluorescent sensing mechanism (IFSM) and microcystin (MC-RR) is selected as a model target. A molecular imprinted thin film is immobilized on the surface of zinc ferrite nanoparticles (ZnFe2O4 NPs) by using arginine, a dummy fragment of MC-RR. By implementation of IFSM on the paper-based microfluidic chip, a versatile platform for the quantitative assay of MC-RR is developed at trace level (the limit of detection of 0.43 μg/L and time of 20 min) in real water samples without any pretreatment. Importantly, the proposed IFSM can be easily modified and extended for the wide variety of species which lack direct interaction with the fluorescent substrate. This work offers the potential possibility to meet the requirements for the on-site analysis and may explore potential applications of molecularly imprinted fluorescent sensors.

In situ immobilization of YVO4:Eu phosphor particles on a film of vertically oriented Y2(OH)5Cl·nH2O nanosheets

A heterostructured photoluminescence 'turn-off' film was developed using vertically oriented LYH:Eu nanosheets as a partial sacrificial layer for isolated YVO₄:Eu³⁺ nanophosphor layers and was used for the convenient detection and removal of Cu²⁺ ions with excellent sensitivity and recyclability.