Encapsulation of melatonin in pH-responsive β-CD nanosponges for enhanced stability and optimized delivery in...

The current study focuses on the development of a pH-responsive nanosponge designed to enhance the stability and controlled release of phytohormone melatonin. The nanosponge, characterized by disulfide bridges and a stabilizer, allows for regulated release in acidic conditions typical of plant rhizospheres. Four different melatonin to nanosponge weight ratios (1:1, 2:1, 3:1 and 4:1) were prepared and analyzed using Ultra Performance Liquid Chromatography to quantify melatonin loading. The optimized ratio (3:1) was characterized by various techniques, including Zeta potential analysis, FESEM-EDX, FTIR, XRD and DSC. In vitro release studies and photostability tests confirmed the effectiveness of nanosponge in controlled melatonin release and enhanced photostability. Melatonin-loaded nanosponges significantly alleviated salinity stress in tomato plants, enhancing yield and reducing the frequency and dosage of melatonin application. This innovative approach promises improved melatonin stability and efficient agricultural use, offering a novel method to mitigate abiotic stress in plants.