Stimuli responsiveness of pollen microgel

Abstract

Lotus pollen, a naturally abundant and structurally robust biomaterial, presents an exciting opportunity for the development of microgels in biomedical and environmental applications. It is through carrying biomolecules by nearly spherical pollen that the microgel can achieve storing and releasing of drugs. This project aims to utilize lotus pollen grains to fabricate microgels and evaluate their responsiveness under pH and ionic conditions. The fabrication method, which includes KOH treatment, was optimized to further enhance the microgel’s performance on swelling. Bovine Serum Albumin (BSA) was also applied to the microgel to study the effect of protein adsorption on pollen size and suspension stability. This study covered lotus pollen that has been defatted and processed to soften, swell, and exhibit gel-like behavior. The produced microgel was added to pH 2 to 12, Calcium Chloride, Sodium Iodide, Potassium Chloride, and BSA solutions. Through particle size analysis, lotus pollen was observed to have a consistent increase in diameter with increasing pH, remains almost unchanged in monovalent cations and BSA solutions, and decreases in solutions with higher divalent cations. It can also swell to a larger diameter compared to the 10% KOH after being processed with 2.5% KOH during fabrication. For the stability analysis, the overall stability of the pollenBSA suspension increases as the pH of the solution increases. The lotus pollen microgel demonstrated tunable swelling behavior and potential functionalization in different fields, highlighting the potential of upcycling natural pollen into sustainable microgel materials for advanced technological applications.