Biodegradability Evaluation of Hydroxyethylcellulose-based Microcapsules by 1H Nuclear Magnetic Resonance Spectroscopy

Abstract This study introduces a robust synthetic method of fabricating co-assembled biodegradable microcapsules composed mainly of representative natural sugar polymers, hydroxyethylcellulose (HEC), alginate, and sorbitol. We propose a facile enzymatic method evaluating initial biodegradation processes of the microcapsules utilizing a linewidth analysis on 1H nuclear magnetic resonance (NMR) spectroscopy. Linewidth analysis on the 1H resonance signals represents that broad resonance signals of the sugar-based microcapsules are changed to relatively narrower signals as an association of cellulase enzyme. This phenomenon explains co-assembled and cross-linked microcapsule structures are destroyed or/and loosened by the enzymatic breakdowns of ester bonds in the microcapsules. Moreover, closer inspection indicates that co-assembled sorbitol molecules are released from the main networked microcapsules, additionally supporting the biodegradation properties of the microcapsules. Considering the unique features of this method, the proposed study provides valuable information about the initial biodegradation processes and mechanisms of various microcapsules.