An Optical Microfiber Biosensor for CEACAM5 Detection in Serum: Sensitization by a Nanosphere Interface

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Optical Sensing

Background:

• Early cancer diagnosis is crucial for effective treatment and improved patient outcomes.
• Carcinoembryonic antigen (CEA)-related cell adhesion molecules 5 (CEACAM5) are significant biomarkers for cancer prewarning.
• Current point-of-care testing (POCT) fiber optic biosensors lack the sensitivity for ultralow concentration detection required for early-stage cancer diagnosis.

Purpose of the Study:

• To develop a highly sensitive fiber optic biosensor for detecting ultralow concentrations of CEACAM5 in serum for early cancer diagnosis.
• To enhance the limit of detection (LOD) of fiber optic biosensors for early-stage cancer biomarker detection.
• To investigate a synergistic sensitization strategy for improved biosensor performance.

Main Methods:

• Functionalization of an optical microfiber sensor with a polystyrene@gold nanosphere (PS@Au nanosphere) interface.
• Utilizing a synergistic sensitization effect combining surface area enlargement and electromagnetic enhancement.
• Testing the sensor's performance in pure solutions and human serum samples.

Main Results:

• Achieved an LOD of 3.54 × 10^-17 M in pure solution and 5.27 × 10^-16 M in serum for CEACAM5 detection.
• Demonstrated an LOD approximately 6 orders of magnitude lower than current methods.
• Validated the sensor's capability for detecting ultralow biomarker concentrations in serum for early cancer detection.

Conclusions:

• The developed optical microfiber sensor with a PS@Au nanosphere interface offers a significant advancement in sensitivity for early cancer detection.
• The synergistic sensitization strategy enhances the performance of fiber optic biosensors, making them viable for effective POCT.
• This approach provides new opportunities for utilizing fiber optic biosensors as competitive POCT tools for early disease diagnosis.