Disposable optical sensor chip for medical diagnostics: new ways in bioanalysis

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Medical Diagnostics

Background:

• Point-of-care diagnostics require rapid, accurate, and user-friendly analytical systems.
• Traditional immunoassays often involve complex procedures like washing and separation steps, limiting their point-of-care applicability.

Purpose of the Study:

• To describe a novel optical sensor system designed for medical point-of-care diagnostics.
• To demonstrate the system's versatility for various immunochemical assay formats.
• To validate the system's performance for detecting specific biomarkers in human serum.

Main Methods:

• Development of a disposable sensor chip with a capillary aperture and a ground plate for biocomponent immobilization.
• Utilizing evanescent field generation via total internal reflection of a laser beam for fluorophor marker excitation.
• Detection of fluorescence using a photomultiplier tube, eliminating the need for washing or separation steps.

Main Results:

• Successful determination of human chorionic gonadotropin (hCG) in serum with a detection limit of 1 ng/mL and high recovery rates.
• Demonstrated feasibility for competitive-type immunoassays, exemplified by the detection of theophylline in serum with a linear calibration curve.
• Achieved low standard deviation (5.6%) in repeated measurements for hCG detection.

Conclusions:

• The described optical sensor system is highly suitable for point-of-care diagnostics due to its efficiency and simplicity.
• The system's ability to perform various immunochemical assays without washing steps offers significant advantages for clinical applications.
• The demonstrated detection of hCG and theophylline validates the system's potential for broad diagnostic utility.