A novel "on-off-on" electrochemiluminescence aptasensor based on resonance energy transfer as signal amplification strategy for ultrasensitive detection of sulfadiazine in different samples.

The misuse of antibiotics may contaminate the environment and cause harm to human health. Therefore, rapid and accurate detection of antibiotics is essential. In this study, a novel electrochemiluminescence resonance energy transfer (ECL-RET) pair was designed using a new ECL emitter (CPM, Ce-TBAPy) as the donor and Co-MOF@AuPt as the acceptor. Moreover, a highly sensitive and specific "on-off-on" ECL aptasensor was constructed for detecting sulfadiazine (SDZ). The aptasensor exhibited a broad linear range (from 10.0 fg mL-1 to 100 ng mL-1) for the SDZ concentration, with limit of detection and limit of quantification values of 1.14 fg mL-1and 3.75 fg mL-1, respectively. The aptasensor achieved good results in spiking experiments with milk and egg samples, and successfully quantified SDZ in fish meal quality control sample. The prepared aptasensor presents great potential for food and environmental safety by detecting antibiotics.

[Study on intra-gastric floating beads of naringenin].

OBJECTIVE: To prepare calcium alginate-chitosan intra-gastric floating beads of naringenin combining with the solid dispersion method and investigate the in vitro floating characteristics, entrapment efficiency and drug release property of the beads. METHODS: The solid dispersion of naringenin was prepared by the Eudragit RLPO. Sodium alginate solution mixed with the powder of the solid dispersion of naringenin and frother was slowly dripped into chitosan-calcium chloride solution added with acetic acid. Calcium alginatechitosan intra-gastric floating beads of naringenin were obtained after drying. The effects of solid dispersion on in vitro release of naringenin were investigated. RESULTS: Intra-gastric floating beads of naringenin were acquired successfully. More than 70% of the beads kept floating in artificial gastric juice in 9 h, the release ratio of naringenin during 9 h was 65%-70% and the entrapment efficiency was about 70%-80%. CONCLUSION: The sustained release of naringenin in the calcium alginate-chitosan intra-gastric floating beads could be achieved by using the solid dispersion method and it provides some ideas of intra-gastric floating preparations.