SNROW-based highly sensitive label-free surface biosensor for hepatitis B detection

Area of Science:

• Nanotechnology
• Biomedical Engineering
• Optical Sensing

Background:

• Hepatitis B virus (HBV) remains a global health issue despite available vaccines.
• Early detection of HBV is critical to prevent disease progression and liver damage.
• Current detection methods may lack the sensitivity for very early-stage diagnosis.

Purpose of the Study:

• To theoretically demonstrate a silicon nanowire optical waveguide for label-free detection of Hepatitis B surface antigen (HBsAg).
• To optimize the waveguide design for enhanced light-analyte interaction and high sensitivity.
• To evaluate the sensor's performance, including its detection limit and sensitivity for HBsAg.

Main Methods:

• Theoretical simulation using finite-element method-based COMSOL Multiphysics.
• Design and optimization of a silicon nanowire rectangular optical waveguide.
• Mimicking biomarker detection segments as adlayers on the waveguide surface.
• Incorporating the waveguide into a Mach-Zehnder interferometer (MZI) for enhanced sensing.

Main Results:

• Achieved ultra-high surface sensitivities: 7.03×2π rad/nm (phase) and 3421.89 µW/nm (MZI).
• Demonstrated an excellent detection limit of 2.92×10⁻³ pg/mm² for HBsAg.
• The sensor can measure HBsAg concentrations as low as 0.00973 ng/mL, enabling early-stage detection.

Conclusions:

• The proposed silicon nanowire optical waveguide sensor offers a highly sensitive and label-free method for HBsAg detection.
• This technology has the potential for early diagnosis of hepatitis B infection.
• The device's sensitivity surpasses requirements for early-stage detection, aiding timely therapeutic intervention.