Automatic Range Adjustment of the Fluorescence Immunochromatographic Assay Based on Image Processing

Area of Science:

• Analytical Chemistry
• Biomedical Engineering
• Image Processing

Background:

• Fluorescence immunochromatographic assay (FICA) is a sensitive, stable, and specific technology used in medical, food, and environmental testing.
• FICA readers with image processing offer portable, rapid point-of-care testing, but common sensors have limited detection ranges.
• High-precision sensors are costly, hindering widespread adoption of FICA readers.

Purpose of the Study:

• To develop an automatic range adjustment mechanism for FICA readers utilizing common CMOS image sensors.
• To overcome the limitations of fixed gray levels in standard image sensors for expanded detection capabilities.
• To improve the cost-effectiveness and accessibility of FICA readers for point-of-care diagnostics.

Main Methods:

• Collected FICA strip images using a standard CMOS image sensor.
• Implemented a novel range adjustment mechanism to automatically control the CMOS sensor's exposure time.
• Validated the method's effectiveness in expanding the detection range of the FICA reader.

Main Results:

• The automatic range adjustment significantly increased detection sensitivity by onefold.
• The upper detection limit of the FICA reader was enhanced twofold.
• Experimental results demonstrated excellent linearity and accuracy, with curve fitting degrees (R²) reaching 0.999.

Conclusions:

• The proposed automatic range adjustment method effectively expands the detection range of image processing-based FICA readers.
• This technique enhances the performance of FICA readers without requiring expensive high-precision sensors.
• The findings support the wider adoption of FICA technology in various diagnostic and monitoring fields.