Keratinocyte-Specific Peptide-Based Surfaces for Hemidesmosome Upregulation and Prevention of Bacterial Colonization

Abstract

Percutaneous devices like orthopedic prosthetic implants for amputees, catheters, and dental implants suffer from high infection rates. A critical aspect mediating peri-implant infection of dental implants is the lack of a structural barrier between the soft tissue and the implant surface which could impede bacteria access and colonization of exposed implant surfaces. Parafunctional soft tissue regeneration around dental implants is marked by a lack of hemidesmosome formation and thereby weakened mechanical attachment. In response to this healthcare burden, a simultaneously hemidesmosome-inducing, antimicrobial, multifunctional implant surface was engineered. A designer antimicrobial peptide, GL13K, and a laminin-derived peptide, LamLG3, were coimmobilized with two different surface fractional areas. The coimmobilized peptide surfaces showed antibiofilm activity against Streptococcus gordonii while enhancing proliferation, hemidesmosome formation, and mechanical attachment of orally derived keratinocytes. Notably, the coatings demonstrated specific activation of keratinocytes: the coatings showed no effects on gingival fibroblasts which are known to impede the quality of soft tissue attachment to dental implants. These coatings demonstrated stability and retained activity against mechanical and thermochemical challenges, suggesting their intraoral durability. Overall, these multifunctional surfaces may be able to reduce peri-implantitis rates and enhance the success rates of all percutaneous devices via strong antimicrobial activity and enhanced soft tissue attachment to implants.

Biomimetic mineralized hybrid scaffolds with antimicrobial peptides

“…As infection is a relevant associated risk in bone and dental regeneration therapies, here we validated the antimicrobial effects of the GL13K peptides absorbed in the mineralized collagen scaffolds against two model bacteria, S. gordonii and E. coli . Previous works have shown the broad-spectrum activity of GL13K against other pathogenic bacteria, such as Pseudomonas aeruginosa , Porphyromonas gingivalis , Fusobacterium nucleatum , Enterococcus faecalis , Staphylococcus aureus and methicillin-resistant S. aureus both in vitro [ 35 , 44 ] and in vivo [ 45 ] as well as in solution [ 46 ] and as coatings on different substrates [ 47 , 48 ]. The antimicrobial potency of the GL13K coating was more noticeable against the Gram-negative E. coli than the Gram-positive S. gordonii bacteria.…”

“…The GL13K-coated mineralized scaffolds were not cytotoxic, which we attributed to the stability of the AMPs coatings as per our previous discussion. The cytocompatibility of the GL13K coatings with other mammalian cells (osteoblasts [ 35 ], fibroblasts [ 9 ], and keratinocytes [ 47 ]) has also been demonstrated when the cells were in direct contact with the AMP coating. Future comprehensive studies with our GL13K-coated mineralized collagen scaffolds will focus on assessing their in vitro osteogenic properties so that we can assess not only the effectiveness of the minerals, but also the effects of the AMP coatings, both from a biological and physicochemical (hydrophobicity) standpoint, to induce osteoblastic differentiation.…”

Culture and characterization of various porcine integumentary-connective tissue-derived mesenchymal stromal cells to facilitate tissue adhesion to percutaneous metal implants

“…Finally, a stringent functional test of the pMSCs’ adhesion to titanium was carried out by subjecting the nine pMSCs seeded on titanium disks to centrifugal forces of 350 g and 500 g, followed by assessing the percentage of cells that remained adhered to titanium post centrifugation. The positive control, keratinocytes with their well described adhesion to Ti [ 22 ], had no significant change in percentage of adhered cells on titanium pre- and post-centrifugation (Fig. 7 c).…”

“…pMSCs (5 × 10 3 ) were seeded onto polished titanium disk surfaces in 48-well plates for 48 h then gently washed thrice with PBS to remove non-adherent cells. Oral keratinocytes (OKF6/TERT-2; BWH Cell Culture and Microscopy Core, Boston, MA) were used as a positive control given their strong adhesion to titanium [ 22 ]. One set of disks ( n = 3) were immediately removed and fixed in 4% paraformaldehyde (hereafter, control-pre).…”

Application of Antimicrobial Peptides on Biomedical Implants: Three Ways to Pursue Peptide Coatings

“…Those discs were thereafter immersed in the peptide solutions of the two peptides GL13K (GKKIK-LKASLKLL) and LAMLG3 (KKGGGPPFLMLLKGSTRFC) that should combine antibiofilm activity (when testing S. gordonii) with enhanced proliferation of human keratinocytes. Beside those obtained effects, the coatings were additionally highly stable to mechanical and thermochemical stress [41].…”