Sulfamethazine detection with direct-binding optical waveguide lightmode spectroscopy-based immunosensor.

Area of Science:

• Biosensing and Analytical Chemistry
• Immunosensor Technology
• Spectroscopy

Background:

• Sulfamethazine (SMZ) is a widely used antibiotic with potential food safety concerns.
• Accurate and sensitive detection methods for SMZ are essential for regulatory compliance and public health.
• Existing detection methods may lack the required sensitivity, specificity, or reusability.

Purpose of the Study:

• To develop and characterize a direct-binding optical waveguide lightmode spectroscopy-based immunosensor for sulfamethazine (SMZ).
• To evaluate the specificity and sensitivity of the developed immunosensor.
• To assess the reusability of the immunosensor for practical screening applications.

Main Methods:

• Constructed a system using a peristaltic pump, injector, He-Ne laser, photodiodes, and a PC.
• Immobilized anti-SMZ antibodies onto a glutaraldehyde-activated sensor chip via covalent binding.
• Utilized Tris-HCl buffer (4mM, pH 7.2) for stable baseline and medium surface coverage.
• Measured sensor response to varying SMZ concentrations and control substances like bovine serum albumin.

Main Results:

• The immunosensor exhibited high specificity, with no response to bovine serum albumin.
• Sensor response showed a linear increase with SMZ concentrations ranging from 10⁻⁸ to 10⁻² M on a semi-logarithmic scale.
• Achieved a limit of detection of 10⁻⁸ M for SMZ.
• Demonstrated favorable reusability of the immunosensor for SMZ screening.

Conclusions:

• The developed optical waveguide lightmode spectroscopy immunosensor is a specific and sensitive tool for sulfamethazine detection.
• The sensor's linear response range and low limit of detection make it suitable for quantitative analysis.
• The reusability of the immunosensor supports its application in routine screening and monitoring.