A chimeric peptide that binds to titanium and mediates MC3T3-E1 cell adhesion

Peptides for bone tissue engineering

Molecular signals in the form of growth factors are the main modulators of cell behavior. However, the use of growth factors in tissue engineering has several drawbacks, including their costs, difficult production, immunogenicity and short half-life. Furthermore, many of them are pleiotropic and, since a single growth factor can have different active domains, their effect is not always fully controllable. A very interesting alternative that has recently emerged is the use of biomimetic peptides. Sequences derived from the active domains of soluble or extracellular matrix proteins can be used to functionalize the biomaterials used as scaffolds for new tissue growth to either direct the attachment of cells or to be released as soluble ligands. Since these short peptides can be easily designed and cost-effectively synthesized in vitro, their use has opened up a world of new opportunities to obtain cheaper and more effective implants for regenerative medicine strategies. In this extensive review we will go through many of the most important peptides with potential interest for bone tissue engineering, not limiting to those that only mediate cell adhesion or induce the osteogenic differentiation of progenitor cells, but also focusing on those that direct angiogenesis because of its close relation with bone formation.

Promotion of minTBP-1-PRGDN on the attachment, proliferation and collagen I synthesis of human keratocyte on titanium

AIM

To investigate the influence of minTBP-1-PRGDN on the attachment, proliferation and collagen I synthesis of human keratocyte on titanium (Ti) surface.

METHODS

The chimeric peptide RKLPDAPRGDN (minTBP-1-PRGDN) was synthesized by connecting RKLPDA (minTBP-1) to the N-terminal of PRGDN, the influence of minTBP-1-PRGDN on the attachment, proliferation and collagen I synthesis of human keratocyte on Ti surface were tested using PRGDN and minTBP-1as controls. The keratocytes attached to the surface of Ti were either stained with FITC-labeled phalloidin and viewed with fluorescence microscope or quantified with alamar Blue method. The proliferation of keratocytes on Ti were quantified with 3-(4,5-dim- ethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide up-taking methods. The secretion of type I collagen were determined using an ELISA kit.

RESULTS

The results showed that minTBP-1-PRGDN at a concentration of 100ng/mL was the most potent peptide to enhance the attachment of human keratocytes to the surface of Ti (1.40±0.03 folds, P=0.003), to promote the proliferation (1.26±0.05 folds, P=0.014) and the synthesis of type I collagen (1.530±0.128, P=0.008). MinTBP-1 at the same concentration could only promote the attachment (1.13±0.04 folds, P=0.020) and proliferation(1.15±0.06 folds, P=0.021), while PRGDN had no significant influence (P>0.05).

CONCLUSION

Our data shows that the novel chimeric peptide minTBP-1-PRGDN could promote the attachment, proliferation and type I collagen synthesis of human keratocytes on the surface of Ti.

Biomimetic coating of magnesium alloy for enhanced corrosion resistance and calcium phosphate deposition

Degradable metals have been suggested as biomaterials with revolutionary potential for bone-related therapies. Of these candidate metals, magnesium alloys appear to be particularly attractive candidates because of their non-toxicity and outstanding mechanical properties. Despite their having been widely studied as orthopedic implants for bone replacement/regeneration, their undesirably rapid corrosion rate under physiological conditions has limited their actual clinical application. This study reports the use of a novel biomimetic peptide coating for Mg alloys to improve the alloy corrosion resistance. A 3DSS biomimetic peptide is designed based on the highly acidic, bioactive bone and dentin extracellular matrix protein, phosphophoryn. Surface characterization techniques (scanning electron microscopy, energy dispersive X-ray spectroscopy and diffuse-reflectance infrared spectroscopy) confirmed the feasibility of coating the biomimetic 3DSS peptide onto Mg alloy AZ31B. The 3DSS peptide was also used as a template for calcium phosphate deposition on the surface of the alloy. The 3DSS biomimetic peptide coating presented a protective role of AZ31B in both hydrogen evolution and electrochemical corrosion tests.