Self-powered biosensing platform for Highly sensitive detection of soluble CD44 protein

Area of Science:

• Biomedical Engineering
• Biosensors
• Electrochemistry

Background:

• Soluble CD44 protein is a biomarker for various cancers.
• Current detection methods may lack sensitivity or require complex sample preparation.
• Enzymatic biofuel cells offer a self-powered platform for biosensing.

Purpose of the Study:

• To develop a self-powered biosensor for ultrasensitive detection of soluble CD44 protein.
• To investigate the feasibility of using an enzymatic biofuel cell for this detection.
• To evaluate the biosensor's performance in terms of sensitivity, stability, and real-world applicability.

Main Methods:

• Fabrication of a biosensor using a co-immobilized aptamer and glucose oxidase bioanode and a bilirubin oxidase modified biocathode.
• Utilizing the open-circuit voltage (E^OCV) as the detection signal.
• Measuring E^OCV changes in response to varying concentrations of soluble CD44 protein.

Main Results:

• The biosensor demonstrated a linear relationship between E^OCV and the logarithm of CD44 protein concentration (0.5-1000 ng mL^-1).
• An ultrasensitive detection limit of 0.052 ng mL^-1 (S/N = 3) was achieved.
• The biosensor exhibited excellent anti-interference, stability (>97% E^OCV after 15 days), and accuracy in real blood samples.

Conclusions:

• The proposed self-powered enzymatic biofuel cell-based biosensor enables ultrasensitive and stable detection of soluble CD44 protein.
• The aptamer-functionalized electrode facilitates electron transfer upon target binding, leading to a measurable signal change.
• This biosensor holds significant potential for early cancer diagnosis using minimally pre-treated blood samples.