Detection of folate binding protein with enhanced sensitivity using a functionalized quartz crystal microbalance...

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Biochemistry

Background:

• Folate binding protein (FBP) is overexpressed in certain malignancies and inflammatory disorders.
• Accurate detection of FBP is crucial for disease diagnosis and monitoring.
• Existing detection methods may lack sensitivity or specificity for clinical applications.

Purpose of the Study:

• To develop a novel quartz crystal microbalance (QCM) biosensor for sensitive and specific detection of FBP.
• To evaluate the performance of the biosensor in terms of detection limit, specificity, and applicability in biological matrices.
• To explore signal enhancement strategies for improved FBP detection.

Main Methods:

• Fabrication of a QCM biosensor by adsorbing a folate-bovine serum albumin (BSA) conjugate onto a gold-coated quartz crystal.
• Assessment of FBP binding and specificity using varying concentrations of folic acid for blocking assays.
• Evaluation of sensor performance in the presence of human blood serum.
• Implementation of a sandwich assay using anti-FBP antibodies and protein-A-coated gold nanospheres for signal amplification.

Main Results:

• The basic folate-BSA QCM biosensor achieved a detection limit of 30 nM for FBP.
• Specific binding of FBP was confirmed, with no non-specific binding observed even at high folic acid concentrations.
• The biosensor demonstrated successful FBP capture in human blood serum.
• The enhanced sandwich assay significantly improved the detection limit to 50 pM, a three-order-of-magnitude enhancement.

Conclusions:

• The developed QCM biosensor offers a sensitive and specific method for FBP detection.
• The assay's ability to function in serum makes it suitable for clinical diagnostics.
• The enhanced sandwich assay provides a highly sensitive platform for FBP quantification.
• This methodology holds potential as a valuable biomarker for diagnosing diseases associated with FBP overexpression.