Anchoring Cu Nanoclusters on Melamine–Formaldehyde Microspheres: A New Strategy for Triggering Aggregation-Induced Emission toward Specific Enzyme-Free Methyl Parathion Sensing

Abstract

Methyl parathion (MP) residues have aroused extensive attention on account of their significant threat to the environment and food safety. Currently reported fluorescent methods used for MP sensing largely depend upon an enzyme. Designing a facile and specific enzyme-free MP fluorescent sensor is in great demand, which remains a challenge. Here, negatively charged Cu nanoclusters (CuNCs) anchored on positively charged melamine–formaldehyde (MF) microspheres (MF@CuNCs) through an electrostatic interaction were prepared. MF microspheres triggered aggregation-induced emission (AIE) of CuNCs and successfully circumvented the shortcomings of poor stability and low luminescence of CuNCs. The fluorescence intensity of MF@CuNCs can be quenched by p-nitrophenol produced by MP under alkaline conditions. Accordingly, a specific enzyme-free MP sensing method was constructed with MF@CuNCs. In combination with a smartphone, visually quantitative analysis of MP in a fast and portable way was also achieved. For the first time, AIE of CuNCs used for enzyme-free MP sensing was successfully explored in this work, and it is believed that this method will open a new pathway for AIE of CuNCs to be applied in various applications.

Simple and sensitive fluorescence sensing of methyl parathion based on the inner filter effect of p‐nitrophenol on nitrogen‐doped titanium carbide quantum dots

“…Compared with chemiluminescence biosensor [42], the proposed sensor exhibits lower LOD and wider linear range. Finally, similar fluorescence biosensors based on QDs are also compared [39, 43]. The linear range is wider, and the LOD is relatively lower.…”

“…However, further increase of pH value leads to no obvious changes in Δ F . It can be attributed that strong alkaline conditions (pH ≥ 12) are favorable to hydrolysis of MP, so that the phosphorous atom of MP is attacked by hydroxide ions to produce p‐NP [39]. Hence, a pH value of 12 is selected for further research.…”

“…Compared with HPLC and electrochemical biosensors [40,41], the proposed fluorescence sensor can avoid complicated pretreatment and modification of electrodes. Compared with ELISA, the method proposed in the current study can avoid the also compared [39,43]. The linear range is wider, and the LOD is relatively lower.…”

Recent advances in aggregation-induced emission (AIE)-based chemosensors for the detection of organic small molecules

“…316 Methyl parathion (MP) sensor C85 relies on the hydrolysis of the insecticide under alkaline conditions into p -nitrophenol to quench its bright orange-red AIE fluorescence via an electron transfer mechanism. 317 C85 , which was constructed by anchoring CuNCs onto melamine-formaldehyde microspheres, was further incorporated into a smartphone-readable platform in which fluorescent colours were digitalized into RBG values by a colour analyzer application. Drawing inspiration from the deactivation of AChE when OPs bind to the serine sites of the enzyme, Wang and Liu et al conjugated LHLHLRL-sequenced peptides onto TPE moiety to afford OP-sensor C86 .…”

Fluorometric and colorimetric dual-mode sensing of α-glucosidase based on aggregation-induced emission enhancement of AuNCs

“…24 Fortunately, aggregation-induced emission enhancement (AIEE) has offered a powerful method to boost the emission efficiency of MNCs through the restriction of intramolecular motions of their capping ligands. 25,26 This fluorescence signal variation characteristic originating from aggregation usually endows the aggregates with high sensitivity and broad chemical detection applicability. 27,28 To the best of our knowledge, multi-mode platforms with self-checking advantages for α-Glu activity determination based on AIEE of MNCs have rarely been developed.…”