Chitosan/iota-carrageenan and chitosan/pectin polyelectrolyte multilayer scaffolds with antiadhesive and bactericidal properties

It has been a challenge to develop durable and cytocompatible antibacterial coatings with antiadhesive and antimicrobial activities. To overcome the problems caused by bacteria contamination on biomedical devices, we are proposing layer-by-layer films based on iota-carrageenan/chitosan, and pectin/chitosan polyelectrolyte multilayers (PEMs) assembled in an acetic acid/acetate buffer solution at pH 5.0. PEMs with 5 and 15 layers are established with chitosan-terminated layers. As compared to pectin, the iota-carrageenan promotes a PEM with a more wettable surface (water contact angle of 25 degrees) and a low roughness. The PEMs have strong antiadhesive and bactericidal activities against Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus). For P. aeruginosa, the effect is seen after 6 h and for S. aureus the effect is seen after 24 h. The antibacterial test in-vitro indicates that PEMs can kill and avoid the attachment of bacteria effectively. To confirm the biomedical potential of these PEMs to act as coatings for tissue scaffolds and implants, adhesion and proliferation of bone marrow-derived stem cells (BMSCs) is demonstrated after 4 and 7 days of incubation. The iota-carrageenan/chitosan PEM supports the BMSCs adhesion, proliferation and spreading, inhibits the attachment and growth of bacteria and promotes cytocompatibility of surfaces.