Polycationic condensed tannin/polysaccharide-based polyelectrolyte multilayers prevent microbial adhesion and proliferation

Abstract Bacterial adhesion and biofilm formation are significant issues associated with microbial infections in biomedical applications. It has been a challenge to prepare durable coatings with antiadhesive and antimicrobial activities. We show that a condensed tannin derivative (amino-functionalized) can be assembled with polysaccharides (pectin and iota-carrageenan) to create polyelectrolyte multilayers (PEMs). PEMs were prepared from the layer-by-layer approach by assembling polycationic-polyanionic pairs in an acetic acid-acetate buffer (pH 5.0). The tannin-based material (polycationic polymer) was characterized by X-ray photoelectron spectroscopy (XPS), while PEMs were characterized through XPS, in-situ Fourier transform surface plasmon resonance, atomic force microscopy, and water contact angle measurements. Compared to the native glass substrate, all PEMs present nanoscale surface roughness, and hydrophilic surfaces. A stability test performed in PBS for 7 days confirms that 15-layer PEMs are durable in aqueous environments. Initial adhesion and antimicrobial tests against Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus) show that the PEMs exhibit antiadhesive and bactericidal activities after 6 h. The antibacterial test in-vitro indicates that PEMs can kill and prevent the attachment and proliferation of bacteria significantly, especially during initial exposure. These PEMs can be applied as coatings to avoid infections imparted by microbial adhesion in biomedical applications.