Creation of 3D chitin/chitosan composite scaffold from naturally pre-structured verongiid sponge skeleton

This study represents the first creation and characterization of a 3D chitin/chitosan composite scaffold derived from the naturally pre-structured skeleton of the cultivated marine demosponge Aplysina aerophoba, aiming to preserve the intricate architecture of the unique tube-like chitin while incorporating chitosan layers. Advanced staining methods, including the use of iodine and Cibacron Brilliant Red (CBR), were employed to distinguish these polysaccharides. ATR-FTIR spectroscopy confirmed the system's structural integrity and identified the optimal chitin/chitosan balance, achieved after 60-minute treatment in 38 % NaOH at 95 °C. Fluorescent microscopy using fluorescein isothiocyanate (FITC) effectively confirmed the presence of chitosan layers in the created chitin/chitosan scaffolds. Scanning electron microscopy analysis further elucidated significant morphological distinctions, where chitin fibers displayed a smooth, uniform surface, contrasting with the ragged and irregular texture of chitosan-containing fibers, indicating significant surface modifications. Zeta potential measurements confirmed the partial transformation of chitin into chitosan. The dual-layer configuration, consisting of a resilient chitin core and a versatile chitosan exterior, not only provides structural support, but also enhances the scaffold's functionality for potential technological and biomedical applications. The preferential metallization of the chitosan phase by copper nanoparticles in the created 3D chitin/chitosan composite opens the way to the potential use of such scaffolds in catalysis.