WEB Design of Multifunctional Peptide Platforms with Antimicrobial and Cell Adhesive Properties to Functionalize Medical ImplantsWednesday (23.09.2020) 10:40 - 10:55 B: Biomaterials Part of:
Implant failure due to bacterial infection and incomplete integration represents a major issue in the fields of orthopedics and dentistry. To overcome this problem, in this study we present the design and development of peptidic platforms that simultaneously reduce bacterial adhesion while enhancing eukaryotic cell adhesion. Such dual activity is achieved by combining the human lactoferrin 1-11 peptide (Lf1-11) with the cell binding motif RGD within a branched molecular scaffold. Furthermore, the peptides contain a catechol group as anchoring unit and poly(ethylene glycol) (PEG) spacers. Different spacer lengths were studied, in order to assess the correlation between the conformation and accessibility of the peptides and the biological response. While the anchoring motif provides a single step immobilization on the titanium surface, the versatility of the synthetic routes allowed for the study of different molecular configurations.
The peptidic platforms significantly improved the adhesion of human mesenchymal stem cells (MSCs) compared to control titanium, but similar values of cell adhesion were observed among all the studied peptides. Interestingly, cell spreading was higher on the surfaces coated with the peptides with a shorter spacer, indicating that above a certain level of length and flexibility of the spacer, the availability of the peptide for cell receptors is compromised. Regarding the adhesion of the Gram positive bacteria Staphylococcus aureus, a significant reduction was observed in all the peptide-functionalized samples, showing values of > 90% of bacterial inhibition. Of note, too long spacer displayed the lowest efficiency. Finally, an analogue replacing linear RGD by its cyclic counterpart, showed a significant enhancement in cell adhesion while retaining the antibacterial properties.
In conclusion, a straightforward and versatile functionalization technique to confer cell adhesive and antibacterial properties to titanium was developed. Our results show that optimal biological responses may be achieved by finely tuning the spacing units and presentation of the peptides.