Bionanocomposite Bamboo: A Regioselective Impregnation with Silver Nanofillers for Antifungal Application

Silver nanoparticles are promising nanofiller materials (Ag-NFs) for reinforcement and anti-bacterial effect in polymers and composites. In this investigation bamboo Dendrocalamus giganteus Munro specimens were impregnated using a colloidal solution of homemade Ag-NFs with the objective of filling up the vascular bundles vessels and improving its resistance to fungi attacks. The metal nanostructured materials with different charged organic ligands (trisodium citrate and chitosan) were used to fill up the internal microenvironment of bamboo. Chemical and physical characterization was made by DLS, UV-VIS, zeta-potential and STEM. The bamboo specimens (5x12x18mm) were submitted to 20 impregnation cycles through a vacuum system. A qualitative characterization of the metal aggregate depositions of impregnated bamboo specimens were analyzed with X-ray microtomography (mu CT) revealing a gradient deposition of citrate-capped Ag-NFs into the parenchyma tissue with higher concentration at the outer part for bamboo, while the chitosancapped Ag-NFs were deposited mainly in the vessel bundles. Both engineered bionanocomposite materials when exposed to air and humidity, after 14 months, the samples were free of fungal colonies, while colonization by the fungal hyphae were present in untreated bamboo specimens.