Calling Biomarkers in Milk Using a Protein Microarray on Your Smartphone.

Area of Science:

• Biotechnology
• Analytical Chemistry
• Biosensing

Background:

• Protein microarrays are valuable for biomarker detection.
• Smartphone-based diagnostics offer portable and accessible testing solutions.
• Multiplexed detection enhances efficiency in biomarker analysis.

Purpose of the Study:

• To develop a smartphone-based protein microarray for multiplexed biomarker detection in milk.
• To validate the system's accuracy using recombinant bovine somatotropin (rbST) and IGF-1 as target biomarkers.
• To demonstrate the potential for on-site food safety and health monitoring.

Main Methods:

• A multiplex immunoassay chip with Quantum Dot (QD) labeling was designed.
• Smartphone camera and custom Android software were used for QD-fluorescence detection and image analysis.
• Recombinant bovine somatotropin (rbST) and IGF-1 detection in milk extracts were performed.
• Results were compared with a flow cytometer reference method.

Main Results:

• The system successfully detected rbST and IGF-1 in milk with reproducible, treatment-dependent biomarker profiles.
• Data showed excellent agreement with flow cytometry reference methods.
• Multiplexed detection of anti-rbST antibodies and IGF-1 was achieved.
• Increased IGF-1 levels were observed in rbST-treated cows.

Conclusions:

• The developed 'protein microarray on a smartphone' concept enables simultaneous, on-site detection of multiple biomarkers.
• This portable technology holds significant potential for applications in food safety, environmental monitoring, and health surveillance.
• The system offers a cost-effective and accessible alternative for complex biomarker analysis.