Conversional fluorescent kiwi peel phenolic extracts: Sensing of Hg2+ and Cu2+, imaging of HeLa cells and their antioxidant activity.

The valorization, resource generation and the functional characteristic exploration of domestic waste still face enormous challenges. Kiwi peels, a common kind of fruit waste, contain a large amount of phenolic substances, including polyphenols, flavonoids, etc., which can be explored and reused in food and biomedical fields. By ultrasonic assisted extraction technology, we obtained conversional fluorescence kiwi peel phenolic extracts (PE) which possessed gradient magenta fluorescence relying on the content of ethanol in the solution, as well as strong antioxidant activity. Besides, metal ions sensing assay revealed that PE can specifically sense Hg2+ and Cu2+ (LOD: 1.16 and 0.17 μM, respectively) accompanied with a fluorescence conversion from magenta fluorescence to blue. Moreover, employing the prepared PE as fluorescent probes, imaging of HeLa cells can be easily achieved with satisfactory resolution. Additionally, PE was incorporated into the gelatin matrix, successfully fabricating a green, edible degradable film with excellent antioxidant activity. Unlabelled Image • Ultrasound treatment accelerated the escape of kiwi peel phenolic extracts. • Phenolic extracts exhibited a gradient magenta fluorescence relying on the solvent effects. • Phenolic extracts sense Hg2+ and Cu2+ with a fluorescence conversion from magenta to blue. • Phenolic extracts were successfully applied to fluorescent imaging of HeLa cells. • Phenolic extracts improved the antioxidant capacity of gelatin-based films. [ABSTRACT FROM AUTHOR]