Green pH/magnetic sensitive hydrogels based on pineapple peel cellulose and polyvinyl alcohol: synthesis, characterization and naringin prolonged release.

This study develops a green method to fabricate pH/magnetic sensitive hydrogels based on pineapple peel carboxymethyl cellulose (PCMC), regenerated nanocellulose (rPPNc), and polyvinyl alcohol (PVA), accompanied by in situ incorporation of FeO. The rPPNc was obtained through a two-stage method involving ionic liquid swelling followed by dilute sulfuric acid hydrolysis. The SEM images revealed the porous structure of the hydrogels. The hydrogels showed a magnetic responsive behavior due to incorporation of FeO, and an enhanced thermal stability at high temperature due to incorporations of rPPNc and FeO. The hydrogels displayed a pH-dependent swelling behavior and swelled more due to incorporation of rPPNc. In addition, rPPNc enhanced the naringin loading and entrapment efficiency of the hydrogels, showing an optimum value at 2% addition. The naringin can be gradually released from the hydrogels, which followed Fickian diffusion model. In summary, this work provided a relatively green approach for producing nanocellulose. The prepared hydrogels can be served as promising candidate materials for drug delivery system due to the characteristics of biocompatibility, pH and magnetic sensitivity.