Direct in vitro selection of titanium-binding epidermal growth factor

Area of Science:

• Biomaterials Science
• Molecular Biology
• Surface Chemistry

Background:

• Titanium dioxide (TiO2) is widely used in biomedical implants.
• Enhancing cell proliferation on implant surfaces is crucial for osseointegration.
• Tailoring growth factors for specific surface affinities remains a challenge.

Purpose of the Study:

• To develop a novel Epidermal Growth Factor (EGF) variant with high affinity for TiO2 surfaces.
• To investigate the ability of the modified EGF to promote cell proliferation on TiO2.
• To establish a method for designing surface-specific growth factors.

Main Methods:

• In vitro selection using ribosome display to identify EGF variants binding to TiO2.
• Solid-phase synthesis and refolding of the selected peptide sequence.
• Molecular dynamic simulations to analyze peptide-TiO2 interactions.
• NIH3T3 cell culture to assess cell proliferation on TiO2 surfaces.

Main Results:

• A novel EGF construct with high affinity for TiO2 was successfully generated.
• The selected peptide segment's hydroxyl groups were critical for TiO2 binding.
• The TiO2-binding EGF enhanced NIH3T3 cell proliferation on titanium surfaces comparable to soluble EGF.
• The engineered EGF induced cell proliferation directly on titanium surfaces.

Conclusions:

• Direct in vitro selection is an effective strategy for designing surface-binding growth factors.
• The engineered EGF promotes cell proliferation on TiO2, with potential applications in biomaterials.
• This approach can be extended to create other surface-specific growth factors for various applications.