Antithyroid drug detection using an enzyme cascade blocking in a nanoparticle-based lab-on-a-chip system

Area of Science:

• Electrochemistry
• Nanomaterials Science
• Biotechnology

Background:

• Methimazole (MT) is a crucial drug for treating hyperthyroidism.
• Accurate and sensitive detection of MT is vital for therapeutic drug monitoring and quality control.
• Existing detection methods may lack sensitivity, speed, or require complex sample preparation.

Purpose of the Study:

• To develop and evaluate a novel biosensor for sensitive methimazole detection.
• To compare the performance of batch and flow-injection analysis modes for MT detection.
• To demonstrate the applicability of the biosensor in real-world samples like human serum and pharmaceuticals.

Main Methods:

• Fabrication of a biosensor using magnetic nanoparticles (MNPs) functionalized with iridium oxide nanoparticles (IrOx NPs) and tyrosinase (Tyr) immobilized on a screen-printed electrode (SPE).
• Evaluation in batch mode via copper chelation and in flow mode using thioquinone formation.
• Utilized a hybrid polydimethylsiloxane/polyester amperometric lab-on-a-chip (LOC) microsystem for flow mode detection.

Main Results:

• Both batch and flow modes exhibited high sensitivity with low limits of detection (LOD) of 0.006 μM and 0.004 μM, respectively.
• The flow mode demonstrated superior advantages including reusability, automation, low sample volume (6 μL), and rapid response time (20 s).
• The biosensor successfully detected methimazole in spiked human serum and pharmaceutical dosage forms.

Conclusions:

• The developed MNP-IrOx NPs-Tyr/SPE nanocomposite biosensor provides a sensitive and efficient platform for methimazole detection.
• The flow-injection analysis mode offers significant advantages for practical applications, enabling rapid, automated, and low-volume sample analysis.
• The biosensor's successful application in real samples validates its potential for clinical and pharmaceutical analysis.