Antimicrobial and controlled release properties of nanocomposite film containing thymol and carvacrol loaded UiO-66-NH2 for active food packaging.

In this work, Zirconium-based metal-organic frameworks (MOFs), UiO-66-NH2, were designed as loading carriers for thymol and carvacrol and added into chitosan to construct antimicrobial packaging films. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA) were applied to characterize the films. Besides, we analyzed the physical properties, mechanical performance, hydrophobicity, release behavior, and antimicrobial capacity of the films. It can be clearly seen that the addition of thymol and carvacrol loaded MOFs into chitosan film significantly improved the thermal stability, light barrier properties, tensile strength, and hydrophobicity. Importantly, UiO-66-NH2 restrained the release rate of thymol and carvacrol compared with pure chitosan film, which endowed efficient antimicrobial capacity against E. coli, S. aureus, and P. citrinum to chitosan films. Overall, the strategy conceived here can be a superior candidate to develop a premium antimicrobial material for active food packaging, which has potential application prospects.

Highly sensitive fluorescent sensing platform for imidacloprid and thiamethoxam by aggregation-induced emission of the Zr(â £) metal - organic framework.

A novel luminescent UiO-66-NH2 (UN) demonstrated great potentials to sense imidacloprid (IM) and thiamethoxam (TH) pesticides with high sensitivity and desirable selectivity. The UN exhibits superb luminescence emission properties, which have been found to enhance the aggregation-induced emission (AIE) of IM and TH. The enhanced AIE of IM and TH on UN has been applied for the sensitive sensing of IM and TH, and a limit of detection (LOD) of IM was estimated to be 5.57 µg/L. LOD of TH was found to be 0.98 µg/L, respectively. Interestingly, the other neonicotinoid pesticides showed a low interference response in recognition of IM and TH. More importantly, we have further demonstrated that the UN are successfully used to sense IM and TH in real samples of fruit juice with a high recovery of 85-116%, and relative standard deviation (RSD) were from 3.42% to 16.07%.