Mucosal attachmentand catalytic functionality of β-galactosidase-loaded polyelectrolyte microcapsules on porcine small-intestinal tissue ex vivo.

A key challenge in the development of localized intestinal enzyme systems is to retain enzyme carriers at the mucosal interface while preserving their catalytic functionality. To our knowledge, retention of enzyme-loaded layer-by-layer polyelectrolyte microcapsules (PMCs) on native small-intestinal mucosa has not previously been demonstrated. In this study, we investigated the ex vivo retention of β-galactosidase-loaded PMCs on porcine small-intestinal mucosa and determined whether the retained capsules preserved catalytic activity. FITC-labelled PMCs were incubated with mucosal explants from the duodenum, jejunum, and ileum and subjected to a standardized washout procedure. Capsule retention was quantified fluorometrically, while PMC-associated surface coverage was assessed by fluorescence microscopy. PMCs showed high retention across all intestinal segments, with a mean retained fraction of approximately 88% and an apparent mucosal surface coverage of approximately 32%. Within the tested conditions, retention was not significantly affected by nominal capsule diameter (1-10 μm), the sacrificial template used for capsule preparation (CaCO3 or MnCO3), NaCl concentration (0-1 M), or Triton X-100 treatment, whereas a significant decrease was observed at pH 4.0. Importantly, PMCs retained on the mucosal tissue remained catalytically active, demonstrating preservation of β-galactosidase functionality after tissue association and washout. These findings provide the first ex vivo demonstration that enzyme-loaded LbL polyelectrolyte microcapsules can be retained on native small-intestinal mucosal tissue while remaining catalytically functional and establish a basis for their further development as mucosa-associated intestinal biocatalytic systems.