A three-dimensional human skin model to evaluate the inhibition of Staphylococcus aureus by antimicrobial peptide-functionalized silver carbon nanotubes. (February 2019)

• Record Type: Journal Article
• Authors: Chaudhari, Atul A; Joshi, Sameer; Vig, Komal; Sahu, Rajnish; Dixit, Saurabh; Baganizi, Rade; Dennis, Vida A; Singh, Shree R; Pillai, Shreekumar
• Is Part Of: Journal of biomaterials applications. Volume 33:Number 7(2019)
• Page Start: 924
• Page End: 934
• Publication Date: 2019-02
• Subjects: Scaffolds -- cells -- skin -- Staphylococcus aureus -- nanotechnology -- antimicrobial peptide -- carbon nanotubes; Biomedical engineering -- Periodicals; Biomedical materials -- Periodicals; 610.28
• DOI: 10.1177/0885328218814984
• Languages: English
• ISSNs: 0885-3282

Abstract

Objective: To investigate the toxicity and antibacterial application of antimicrobial peptide-functionalized silver-coated carbon nanotubes against Staphylococcus infection using a full thickness human three-dimensional skin model. Materials and methods: The three-dimensional skin formation on the scaffolds was characterized by electron microscopy and investigation of several skin cell markers by real time–reverse transcriptase polymerase chain reaction. Functionalized silver-coated carbon nanotubes were prepared using carboxylated silver-coated carbon nanotubes with antimicrobial peptides such as TP359, TP226 and TP557. Following the characterization and toxicity evaluation, the antibacterial activity of functionalized silver-coated carbon nanotubes against Staphylococcus aureus was investigated using a bacterial enumeration assay and scanning electron microscopy. For this purpose, a scar on the human three-dimensional skin grown on Alvetex scaffold using keratinocytes and fibroblasts cells was created by taking precaution not to break the scaffold beneath, followed by incubation with 5 µg/mL of functionalized silver-coated carbon nanotubes re-suspended in minimum essential medium for 2 h. Post 2-h incubation, 200 µL of minimum essential medium containing 1 × 10 4 colony forming units of Staphylococcus aureus were incubated for 2 h. After incubation with bacteria, the colony forming unit/gram (cfu/g) of skin tissue were counted using the plate count assay and the samples were processed for scanning electron microscopy analysis. Results: MTT assay revealed no toxicity of functionalized silver-coated carbon nanotubes to the skin cells such as keratinocytes and fibroblasts at 5 µg/mL with 98% cell viability. The bacterial count increased from 10 4 to 10 8 cfu/g in the non-treated skin model, whereas skin treated with functionalized silver-coated carbon nanotubes showed only a small increase from 10 4 to 10 5 cfu/g (1000-fold viable cfu difference). Scanning electron microscopy analysis showed the presence of Staphylococcus aureus on the non-treated skin as opposed to the treated skin. Conclusion: Thus, our results showed that functionalized silver-coated carbon nanotubes are not only non-toxic, but also help reduce the infection due to their antibacterial activity. These findings will aid in the development of novel antibacterial skin substitutes.