How Crystallographic Orientation-Induced Fibrinogen Conformation Affects Platelet Adhesion and Activation on TiO₂

Area of Science:

• Biomaterials Science
• Surface Chemistry
• Hematology

Background:

• Protein adsorption significantly impacts biomaterial performance in medical implants.
• Human plasma fibrinogen (HPF) conformation dictates platelet behavior and thrombosis risk at the blood-biomaterial interface.
• Surface crystallographic orientation of biomaterials can control adsorbed HPF conformation.

Purpose of the Study:

• To investigate how different rutile (TiO2) surface crystallographic orientations affect HPF adsorption and conformation.
• To determine the impact of HPF conformation on specific rutile facets on platelet adhesion and activation.
• To establish a link between surface properties, protein conformation, and biological response.

Main Methods:

• Utilized four low-index rutile TiO2 facets: (110), (100), (101), and (001).
• Employed scanning electron microscopy (SEM) to analyze platelet morphology.
• Measured P-selectin expression to quantify platelet activation.
• Applied atomic force microscopy (AFM) and immunochemical analysis to study HPF conformation.

Main Results:

• Platelet adhesion and activation were suppressed on (110) facets.
• Extensive platelet adhesion and activation were observed on (001) facets.
• HPF adsorbed in a trinodular conformation on (110) facets, masking platelet-binding sequences.

Conclusions:

• Rutile surface crystallographic orientation critically influences HPF conformation and subsequent platelet response.
• Controlling surface facet can mitigate pathological clot formation and thromboembolic complications.
• This study offers insights into designing biomaterials with tailored bioactivity by controlling crystal facet exposure.