A simple unlabeled human chorionic gonadotropin biosensor based on a peptide aptamer.

Area of Science:

• Biochemistry
• Biosensor Technology
• Analytical Chemistry

Background:

• Human chorionic gonadotropin (HCG) is a key biomarker for pregnancy and oncology.
• Current HCG detection methods, such as colloidal gold assays and biochemical analyzers, suffer from inaccuracy or complexity.
• There is a need for a simple, sensitive, and accurate HCG detection method.

Purpose of the Study:

• To construct an accurate, sensitive, and simple unlabeled biosensor for HCG detection.
• To utilize a novel peptide aptamer for HCG recognition.
• To validate the biosensor's performance for potential use as a portable diagnostic device.

Main Methods:

• Peptide aptamer design and simulation using Molecular Operating Environment (MOE).
• Western blot (WB) to verify aptamer-protein binding.
• Electrochemical deposition on screen-printed electrodes (SPEs) followed by aptamer self-assembly.
• Blocking with 6-mercapto-1-hexanol (MCH) and Bovine Serum Albumin (BSA).
• Electrochemical impedance spectroscopy (EIS) for HCG quantification.

Main Results:

• The peptide aptamer showed effective binding to HCG.
• The developed biosensor exhibited a linear response in the range of 5-1500 mIU mL⁻¹.
• A low detection limit of 1 mIU mL⁻¹ was achieved.
• The biosensor demonstrated stability at room temperature for 14 days.

Conclusions:

• The novel peptide aptamer-based biosensor provides a sensitive and accurate method for HCG detection.
• The biosensor overcomes limitations of existing HCG detection techniques.
• Its characteristics suggest potential for development into a portable HCG diagnostic device.