Inflammatory biomarker detection in milk using label-free porous SiO₂ interferometer

Area of Science:

• Biomedical Engineering
• Biosensing Technology
• Veterinary Diagnostics

Background:

• Bovine mastitis (BM) is a costly dairy cattle disease linked to production loss and poor animal health.
• N-acetyl-β-d-glucosaminidase (NAGase) is a biomarker for tubular cell damage, indicating nephrological disorders and BM.

Purpose of the Study:

• To develop a novel reflective optical assay for early bovine mastitis (BM) diagnosis.
• To utilize N-acetyl-β-d-glucosaminidase (NAGase) levels in whole milk for inflammation detection.

Main Methods:

• Employing gelatin-functionalized porous silicon Fabry-Pérot interferometers as optical transducers.
• Monitoring lysosomal activity via reflectometric interference spectroscopy based on refractive index changes.
• Calibrating the assay within clinically relevant BM concentrations (1.04-16.7 μM min⁻¹ dynamic range, 0.49 μM min⁻¹ detection limit).

Main Results:

• The optical assay successfully detected NAGase activity in various inflammation stages (healthy, subclinical, clinical).
• Biosensor performance correlated with gold standard methods, showing increased NAGase with higher somatic cell counts.
• The assay demonstrated a clinically relevant dynamic range and a low detection limit.

Conclusions:

• The developed biosensor enables convenient, early diagnosis and classification of bovine mastitis (BM).
• This optical assay addresses limitations of conventional diagnostic practices for dairy cattle health.
• The study presents a promising bio-diagnostic sensing system for veterinary applications.