Direct Optical Detection of Factor Xa Activity in Minimally Processed Whole Blood

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Hematology

Background:

• Direct measurement of factor Xa activity in whole blood is crucial for personalized anticoagulant therapy.
• Current methods often require complex sample processing, limiting point-of-care applications.
• Anticoagulant-associated complications, such as bleeding, necessitate improved monitoring strategies.

Purpose of the Study:

• To develop a method for direct optical detection of factor Xa activity in minimally processed whole blood.
• To enable point-of-care monitoring of anticoagulant therapy.
• To correlate sensor measurements with established clinical assays.

Main Methods:

• Utilized a custom Förster Resonance Energy Transfer (FRET)-pair labeled DNA-peptide substrate.
• Employed a tapered-fiber sensor for evanescent fluorescence detection, minimizing background interference.
• Validated measurements against a standard chromogenic assay and activated partial thromboplastin time (aPTT).

Main Results:

• Demonstrated detection of endogenous factor Xa activity in over 85% of whole blood samples.
• Successfully detected therapeutic enoxaparin concentrations in 90% of whole blood samples within an hour.
• Established a correlation between fiber-based measurements and aPTT testing.

Conclusions:

• The developed FRET-based fiber optic sensor enables direct optical detection of factor Xa activity in whole blood.
• This technology shows promise for point-of-care monitoring of anticoagulant therapy.
• Potential to personalize anticoagulant dosage and reduce associated adverse events.