Characterization of aTiO₂ surfaces functionalized with CAP‐p15 peptide

Abstract

Functionalization of Titanium implants using adequate organic molecules is a proposed method to accelerate the osteointegration process, which relates to topographical, chemical, mechanical, and physical features. This study aimed to assess the potential of a peptide derived from cementum attachment protein (CAP‐p15) adsorbed onto aTiO2 surfaces to promote the deposition of calcium phosphate (CaP) minerals and its impact on the adhesion and viability of human periodontal ligament cells (hPDLCs). aTiO2 surfaces were synthesized by magnetron sputtering technique. The CAP‐p15 peptide was physically attached to aTiO2 surfaces and characterized by atomic force microscopy, fluorescence microscopy, and water contact angle measurement. We performed in vitro calcium phosphate nucleation assays using an artificial saliva solution (pH 7.4) to simulate the oral environment. morphological and chemical characterization of the deposits were evaluated by scanning electronic microscopy (SEM) and spectroscopy molecular techniques (Raman Spectroscopy, ATR‐FTIR). The aTiO2 surfaces biofunctionalized with CAP‐p15 were also analyzed for hPDLCs attachment, proliferation, and in vitro scratch‐healing assay. The results let us see that the homogeneous amorphous titanium oxide coating was 70 nanometers thick. The CAP‐p15 (1 μg/mL) displayed the ability to adsorb onto the aTiO2 surface, increasing the roughness and maintaining the hydrophilicity of the aTiO2 surfaces. The physical adsorption of CAP‐p15 onto the aTiO2 surfaces promoted the precipitation of a uniform layer of crystals with a flake‐like morphology and a Ca/P ratio of 1.79. According to spectroscopy molecular analysis, these crystalline deposits correspond to carbonated hydroxyapatite. Regarding cell behavior, the biofunctionalized aTiO2 surfaces improved the adhesion of hPDLCs after 24 h of cell culture, achieving 3.4‐fold when compared to pristine surfaces. Moreover, there was an increase in cell proliferation and cell migration processes. Physical adsorption of CAP‐p15 onto aTiO2 surfaces enhanced the formation of carbonate hydroxyapatite crystals and promoted the proliferation and migration of human periodontal ligament‐derived cells in in vitro studies. This experimental model using the novel bioactive peptide CAP‐p15 could be used as an alternative to increasing the osseointegration process of implants.

Amorphous titanium oxide (aTiO2) thin films biofunctionalized with CAP-p15 induce mineralized-like differentiation of human oral mucosal stem cells (hOMSCs)

“…In a recent investigation [16] we evaluated the water contact angle of bare and functionalized aTiO 2 surfaces with CAP-p15, demonstrating that aTiO 2 -CAP-p15 surfaces kept their hydrophilic nature. This could be related to the charge and polar amino acids exposed on the surface, creating hydrogen bonds with water droplets.…”

“…CAP-p15 functionalization of aTiO 2 -coated samples was performed by peptide physical adsorption as previously described [16]. Briefly, the lyophilized peptide was resuspended at a concentration of 1 µg ml −1 in purified deionized water, then, aTiO 2 -coated samples were individually placed in a 24-well plate and covered with 300 µl of the peptide dissolution, carefully distributed over the whole surface of the aTiO 2 -coated samples.…”

“…In a recent paper, we reported the immobilization by physical adsorption of a novel peptide sequence, CAP-p15, onto an amorphous titanium oxide layer (aTiO 2 ) that simulates the surface of a Tibased implant [16]. This sequence of 15 amino acid residues is derived from the C-terminal region of the cementum attachment protein (CAP) and possesses acidic and hydrophobic properties.…”

“…This sequence of 15 amino acid residues is derived from the C-terminal region of the cementum attachment protein (CAP) and possesses acidic and hydrophobic properties. More importantly, CAP-p15 exhibited the ability to facilitate carbonate hydroxyapatite crystal formation, enhancing cell attachment, influencing cytoskeleton organization, and improving cell proliferation and migration of human periodontal ligament cells in vitro [16][17][18].…”