A microbial infection‐resistant 3D bioprinted material for corneal stroma regeneration

Abstract

Aims/Purpose: To assess whether 3D bioprinted, scaffold‐immobilized antimicrobial peptides (AMPs) derivatives, BMAP27(1–18) and hLF(1–11) can inhibit microbial colonization to obtain infection‐resistant 3D bioprinted hemi‐corneas.Methods: The research followed the tenets of the Declaration of Helsinki. 3D bioprinting was used to produce transparent nanocellulose‐ and alginate‐based 3D constructs. Functionalized 3D bioprinted scaffolds with AMPs were characterized by contact angle and transparency measurements. The antimicrobial and antifungal activity of the peptides in solution were investigated by minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) methods against Staphylococcus epidermidis ATCC 35984, S. aureus ATCC 25923, S. epidermidis ATCC 12228, Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC 25922 and Candida albicans ATCC 90028. The antimicrobial activity of the AMP‐modified scaffolds was studied against P. aeruginosa and C. albicans reference strains by colony forming unit (CFU) counts, and their biocompatibility was investigated by measuring the viability of primary human/cadaver‐isolated corneal stromal‐mesenchymal stromal cells (CS‐MSCs).Results: The original and modified peptides showed MIC (MBC) values of 1–4 (2–8) μM and 16 – >128 (32 – >128) μM, respectively, against S. epidermidis ATCC 35984, S. aureus, S. epidermidis ATCC 12228, P. aeruginosa, E. coli and C. albicans, while ncBP‐BMAP27(1–18) and ncBP‐hLF(1–11) values were 1–16 (2–32) μM 4–128 (4 – >128) μM, respectively, against all the pathogens. The modified scaffolds containing the AMPs attached to the scaffolds, demonstrated the ability to kill 20–96% of P. aeruginosa, and between 60–70% of C. albicans. All the 3D bioprinted scaffolds showed no cytotoxicity towards CS‐MSCs.Conclusions: We could successfully combine 3D bioprinting with immobilization of AMPs that show promising antimicrobial activity against two of the most dangerous pathogens to the cornea, while a good cytocompatibility for the CS‐MSCs could be achieved. Optimal bioink composition and cellularization of tissue equivalents are essential in fine‐tuning a method to promote the current 3D bioprinting technique as a future treatment modality for corneal regeneration.