Abstract
A rapid, label-free on-line virus detection method has been developed based on opto-fluidic ring resonator (OFRR). The OFRR employs a fused silica capillary with a diameter around 100 gm. The circular cross section of the capillary forms the ring resonator that supports the whispering gallery modes (WGMs). The OFRR wall is only a few micrometers. Thus, the evanescent field of the WGMs extends into the core and interacts with the sample flowing in the core. The WGM spectral position shifts in response to the binding of biomolecules to the OFRR inner surface, providing quantitative and kinetic information about the biomolecule interaction.
In this work, M13 filamentous phage and anti-M13 antibody are chosen as a model system to demonstrate the detection and quantification of virus in liquid samples. Anti-M13 antibodies are first covalently attached on the aminosilane coated OFRR surface to provide a bioselective layer. The detection is then performed when the virus concentration varies from 10(11) pfu/mL down to 10(3) pfu/mL. Our experimental results show that the OFRR is capable of detecting M13 at a concentration as low as 1000 pfu/mL. Control experiments are carried out to show the specificity of the detection. A theoretical model is developed to analyze the experimental results. The OFRR are advantageous in virus detection, as it integrates the ring resonator with fluidic channels and provides continuous on-line monitoring capability. It also has great potential for sensitive, rapid, and low-cost micro total analysis devices for biomolecule detection.