Enhanced pollen microgels as pH-responsive drug carriers

Abstract

This study illustrated the promising capabilities of enhanced pollen microgels as stimuli-responsive drug carriers. Microgels were prepared by incubating in varying concentrations of potassium hydroxide (KOH), and their morphology and swelling behaviors at different pH levels were characterized using FlowCam dynamic image particle analyzer and light microscope. Sunflower and camellia pollen exhibited pH-dependent swelling, with maximum swelling observed at pH 10, induced by the deprotonation of carboxylic groups in the intine layer. Modulation of the incubation stage via optimization of KOH concentration led to microgels exhibiting a 49.56% increase above previously reported values. Drug release studies were conducted using FITC-BSA, doxorubicin hydrochloride (DOX) and rhodamine B (RhB) as drug models. While release of FITC-BSA was highest at pH 2, release profiles of DOX showed comparable results at pH 2 and pH 10, and release rate of RhB was highest at pH 10. These findings highlight the potential of pollen microgels as environment-responsive drug carriers for various biomedical applications, and also underscores the need to achieve predictable and drug-specific release kinetics.