Rapid and Label-Free Detection of Porcine Reproductive and Respiratory Syndrome Virus on Nanoscale by Biosensor Based on Imaging Ellipsometry

Abstract

This study describes a simple and rapid method for virus detection on nanoscale measurement utilizing biosensor based on imaging ellipsometry. Porcine reproductive and respiratory syndrome virus (PRRSV) was served as an experimental model for demonstration. Staphylococcal protein A was firstly attached onto carboxyl-modified silicon substrate and purified anti-PRRSV IgG obtained from hyperimmune sera combined with Protein A for oriented immobilization to form capture layer. PRRSV in samples can then be specifically grabbed onto the capture layer. The signal (grayscale value) after virus combination is intuitively quantified by imaging ellipsometry. The minimum detection limit was as low as 2.4 × 10³ median cell infectious dose (CCID₅₀ mL⁻¹) infectious virus. Application the proposed method to 20 clinic samples demonstrated that the result was significant correlated (R = 0.85) with virus isolation. The detection time was only 20 min expended.

Keywords:

• Biosensor
• Imaging Ellipsometry
• PRRSV

Acknowledgments

The authors are gratefully to Yuhe Li for his gift of purified PRRSV antisera and Junbin Liu for his collection of clinic sample, and they are both worked in Yangzhou Unibio Ltd., Yangzhou, China. Thanks also gifts to Natural Science Foundation (10804083, 20845003) of China and open funds (NJ2009-04) from key laboratory of Sichuan, China.