The interactions of thrombin with borosilicate glass surfaces

Area of Science:

• Biomaterials Science
• Surface Chemistry
• Protein Adsorption

Background:

• Understanding protein adsorption to biomaterial surfaces is crucial for medical device design.
• Thrombin, a key enzyme in coagulation, can adsorb to various materials, potentially affecting its function.

Purpose of the Study:

• To quantify thrombin adsorption kinetics and stability on borosilicate glass and poly(methyl methacrylate) surfaces.
• To investigate the desorption behavior and potential denaturation of adsorbed thrombin.

Main Methods:

• Thrombin adsorption was measured on borosilicate glass and PMM vessels using a clotting time assay.
• Desorption kinetics were studied by sequentially washing adsorbed thrombin from glass capillaries.
• Surface-bound thrombin was quantified using a fibrinogen clotting assay after varying buffer wash times.

Main Results:

• Thrombin adsorption to PMM was minimal, validating the experimental method.
• Borosilicate glass exhibited significant thrombin adsorption with an association constant of 1.8 x 10(7) l./mol.
• Adsorbed thrombin on glass showed surface denaturation at a rate of 2.5%/min.
• Desorption occurred in multiple phases: rapid (<90% within 2 min), intermediate (~8% within 30 min), and slow (remaining after 1440 min).

Conclusions:

• Borosilicate glass demonstrates substantial thrombin adsorption with associated denaturation.
• The desorption of thrombin from glass surfaces is a multi-phasic process.
• Surface properties and batch variations influence thrombin adsorption and desorption behavior.