Patent ID: 7312069
Filing Date: 2007-12-25
Classification: G01N,Y10S

Abstract:
1. A method for analyzing a ligand in a sample, comprising the steps of: causing a sample containing a ligand and a metal thin film to contact each other, wherein a receptor that can bind specifically to a ligand is immobilized on one side of the metal thin film, an optical prism is provided on an opposite side of the metal thin film, and the metal thin film can cause surface plasmon resonance, so that the ligand in the sample binds to the receptor; irradiating the side of the metal thin film opposite to the side on which the receptor is immobilized with measuring light using irradiating means for irradiating with measuring light; receiving reflected light of the measuring light reflected on the side of the metal thin film using light receiving means for receiving reflected light of the measuring light; and detecting a change in a surface plasmon resonance angle caused by a change in a dielectric constant of a vicinity of the metal thin film, based on the reflected light, using analyzing means for analyzing a ligand binding to the receptor; further comprising applying external vibration to the side of the metal thin film on which the receptor is immobilized, using applying means for applying external vibration to a region in which the receptor is immobilized, while irradiating the metal thin film with the measuring light using the irradiating means; and obtaining frequency characteristics of a surface plasmon resonance angle with respect to external vibration using the analyzing means, and based on the frequency characteristics, analyzing a ligand in the sample binding to the receptor, and wherein the analyzing means further includes comparing means for comparing a phase of the external vibration with a phase of a signal component of the external vibration included in the reflected light, and the step of obtaining the frequency characteristics compares the phase of the external vibration with the phase of the signal component of the external vibration included in the reflected light, using the comparing means, to detect a point of inflection of the frequency characteristics.