Polymeric Multilayers that Contain Silver Nanoparticles can be Stamped onto Biological Tissues to Provide Antibacterial Activity

• Published in: Advanced functional materials 2011-05, Vol.21 (10), p.1863-1873
• Main Authors: Agarwal, Ankit, Guthrie, Kathleen M., Czuprynski, Charles J., Schurr, Michael J., McAnulty, Jonathan F., Murphy, Christopher J., Abbott, Nicholas L.
• Format: Article
• Language: English
• Subjects: Bacteria; Beads; Biomedical materials; Elastomers; microparticles; Multilayers; Polyelectrolytes; Polymer multilayers; Pseudomonas aeruginosa; Silver; silver-nanoparticles; stamping; Staphylococcus epidermidis; wounds
• ISSN: 1616-301X; 1616-3028; 1616-3028
• DOI: 10.1002/adfm.201002662

The design of polyelectrolyte multilayers (PEMs) that can be prefabricated on an elastomeric stamp and mechanically transferred onto biomedically‐relevant soft materials, including medical‐grade silicone elastomers (E’∼450–1500 kPa; E’‐elastic modulus) and the dermis of cadaver skin (E’∼200–600 kPa), is reported. Whereas initial attempts to stamp PEMs formed from poly(allylamine hydrochloride) and poly(acrylic acid) resulted in minimal transfer onto soft materials, we report that integration of micrometer‐sized beads into the PEMs (thicknesses of 6–160 nm) led to their quantitative transfer within 30 seconds of contact at a pressure of ∼196 kPa. To demonstrate the utility of this approach, PEMs were impregnated with a range of loadings of silver‐nanoparticles and stamped onto the dermis of human cadaver skin (a wound‐simulant) that was subsequently incubated with bacterial cultures. Skin dermis stamped with PEMs that released 0.25 ± 0.01 μg cm−2 of silver ions caused a 6 log10 reduction in colony forming units of Staphylococcus epidermidis and Pseudomonas aeruginosa within 12 h. Significantly, this level of silver release is below that which is cytotoxic to NIH 3T3 mouse fibroblast cells. Overall, this study describes a general and facile approach for the functionalization of biomaterial surfaces without subjecting them to potentially deleterious processing conditions. The design of polymeric films containing micrometer‐sized beads that can be prefabricated on an elastomeric stamp and mechanically transferred onto biomedically relevant soft materials, such as silicone sheets or biological tissues, is reported. The dermis of human cadaver skin (a wound simulant) stamped with silver nanoparticle‐loaded films is shown to exhibit antibacterial activity against bacteria commonly isolated from wound infections.