Abstract: This method for detecting a target particle comprises (a) preparing a solution containing a target particle, a luminescent probe that binds to the target particle and a particle for separation and recovery, or containing the target particle bound to the luminescent probe, the luminescent probe and the particle for separation and recovery, and forming a complex composed of the target particle, the luminescent probe and the particle for separation and recovery in the solution, (b) recovering the particle for separation and recovery from the solution by solid-liquid separation treatment after the (a) and preparing a sample solution containing the particle for separation and recovery, and (c) calculating the number of the complex present in the sample solution according to a scanning molecule counting method, wherein the particles for separation and recovery bind to a complex composed of the target particles and the luminescent probe.

Abstract: There is provided a single particle detection technique based on a scanning molecule counting method, enabling individual detection of a single particle using light measurement with a confocal or multiphoton microscope, and quantitative observation of conditions or characteristics of the particle. The inventive technique of detecting a single particle in a sample solution detects light containing substantially constant background light from a light detection region with moving the position of the light detection region of the microscope in a sample solution to generate time series light intensity data; and detects individually a light intensity reduction occurred when a single particle which does not emit light (or a particle whose emitting light intensity in a detected wavelength band is lower than the background light) enters in the light detection region in the time series light intensity data as a signal indicating the existence of each single particle.

Abstract: There is provided a structure to make the setting of a criterion for eliminating noises easy in the scanning molecule counting method. In the inventive optical analysis technique of detecting light of a light-emitting particle in a sample solution, time series light intensity data of light from a light detection region detected with moving the position of the light detection region in the sample solution is generated, and a signal of a light-emitting particle individually is detected in the time series light intensity data, wherein a signal having a light intensity in a light intensity range set based upon a signal generation frequency integrated value distribution which is a distribution, obtained by using as a variable an intensity of a signal, of integrated values of generation frequencies of signals having an intensity not lower than the variable is extracted as the signal of the light-emitting particle.

Abstract: The inventive technique of detecting and analyzing light from a light-emitting particle in accordance with the scanning molecule counting method using an optical measurement with a confocal microscope or a multiphoton microscope is characterized by detecting intensities of components of two or more wavelength bands of light from a light detection region of an optical system with moving the position of the light detection region in a sample solution by changing the optical path of the optical system of the microscope; detecting individually signals of the light from each light-emitting particle in the intensities of the components of the two or more wavelength bands of the detected light; and identifying a kind of light-emitting particle based on the intensities of the components of the two or more wavelength bands of the signals of the light of the detected light-emitting particle.

Abstract: There is provided an optical analysis technique enabling identification of a kind of light-emitting particle corresponding to a signal on a time series light intensity data or identification of a signal corresponding to light-emitting particles other than a particle to be observed in an optical measurement using a confocal microscope or a multiphoton microscope. The inventive optical analysis technique measures simultaneously and separately intensities of lights of two or more wavelength bands from a light detection region in a sample solution containing light-emitting particles of two or more kinds to generate time series light intensity data of the respective wavelength bands; detects signals simultaneously generated on the time series light intensity data of at least two wavelength bands; and identifies the simultaneously generated signals as signals of a light-emitting particle of at least one specific kind.