Molecular plasma deposited peptides on anodized nanotubular titanium: an osteoblast density study

A large amount of work is currently being conducted to design, fabricate, and characterize materials coated or immobilized with bioactive molecules for tissue engineering applications. Here, a novel method, molecular plasma deposition (MPD), is introduced with can efficiently coat materials with numerous bioactive peptides. Specifically, here, RGDS (arginine-glycine-aspartic acid-serine), KRSR (lysine-arginine-serine-arginine), and IKVAV (isoleucine-lysine-valine-alanine-valine) were coated on anodized nanotubular titanium using MPD. The anodized nanotubular titanium surfaces were characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), and water contact angle measurements. Peptide coatings were examined by X-ray photoelectron spectroscopy (XPS) and an amine reactive fluorescence molecule, 3-(4 carboxybenzoyl)quinoline 2-carboxaldehyde (CBQCA). Electrospray ionization (ESI) was used to confirm peptide integrity. Osteoblast (bone-forming cell) density was determined on the materials of interest. Results confirmed peptide coatings and showed that the MPD RGDS and KRSR coatings on anodized nanotubular titanium increased osteoblast density compared with uncoated substrates and those coated with IKVAV and a control peptide (RGES) after 4 h and 7 days. SEM confirmed differences in the morphology of the attached cells. These results, to the best of our knowledge, are the first reports using MPD to efficiently create peptide coatings to increase osteoblast density on metals commonly used in orthopedics. Since MPD represents a quick, inexpensive, and versatile technique to coat implants with peptides, it should be further studied for numerous implant applications.