A diagnostic electrochemical aptasensor development for sCD80 protein detection in human serum

Area of Science:

• Biomedical Engineering
• Biosensor Technology
• Analytical Chemistry

Background:

• Elevated soluble CD80 (sCD80) levels in serum are linked to autoimmune diseases like rheumatoid arthritis (RA), indicating its potential as a diagnostic biomarker.
• Current methods for sCD80 detection, such as immunoassays, suffer from drawbacks including cross-reactivity, necessitating the development of more accurate detection techniques.

Purpose of the Study:

• To develop and validate a novel aptamer-based biosensor (aptasensor) for the sensitive and specific detection of sCD80.
• To establish a label-free electrochemical detection platform for sCD80 quantification in biological samples.

Main Methods:

• Selection of a high-affinity DNA aptamer for sCD80 using the SELEX process (K_d = 47.69 nM).
• Development of a label-free aptasensor on a screen-printed gold electrode (AuSPE) platform utilizing electrochemical impedance spectroscopy (EIS).
• Characterization of aptamer immobilization and sCD80 binding using photo-induced force microscopy (PIFM).

Main Results:

• The aptasensor demonstrated a linear detection range from 0.025 to 10.0 nM for sCD80, with a low limit of detection (LOD) of 8.0 pM.
• The sensor exhibited high performance in a biological matrix, showing a linear response to spiked sCD80 with R² = 0.9887.
• Accurate recovery (105-125%) and low coefficient of variation (<7%) confirmed the aptasensor's reliability for detecting sCD80 in complex samples.

Conclusions:

• A novel, sensitive, and specific aptasensor for sCD80 detection has been successfully developed on an AuSPE platform.
• The aptasensor offers a promising label-free electrochemical method for sCD80 quantification, overcoming limitations of traditional immunoassays.
• This aptasensor holds significant potential for the early diagnosis and monitoring of RA and other autoimmune diseases.