Abstract: A method for determining a state of a cell, the cell being placed in a sample, in contact with a culture medium, the method comprising: illuminating the sample with a light source and acquiring an image of the sample with an image sensor, the image sensor lying in a detection plane; from the acquired image, locating a position of the cell in a plane parallel to the detection plane; the method further comprising: from the acquired image, estimating a refractive index of the cell or a relative refractive index of the cell, the relative refractive index corresponding to a refractive index of the cell relative to the refractive index of the culture medium; from the estimation of the refractive index or of the relative refractive index, determining an index of interest of the cell; from the index of interest, classifying a state of the cell among predetermined states, the predetermined states comprising at least one apoptosis state and one living state.

Abstract: An analysis system features a confinement device, an optical measurement device, a flow device, a collecting conduit, and an actuation device. The confinement device comprises a measurement chamber, optically transparent first and second measurement surfaces that face each other across a distance that defines a thickness of the measurement chamber, and a flexible membrane that forms a seal with the measurement surfaces to laterally delimit the measurement chamber. When the collecting is sealed with a container, a connection is established that permits a liquid sample to be collected from the container. The optical measurement device emits light towards the chamber and detects light that has been transmitted through it, wherein the flow device causes liquid to flow through the collecting conduit between the container and the measurement chamber. The actuation device varies the thickness.

Abstract: A method for holographic characterization of a particle contained in a sample, based on an image, or hologram, of the sample obtained by an image sensor when the sample is illuminated by a light source. The hologram is the subject of a holographic reconstruction, to obtain a reference complex image, representative of the light wave transmitted by the sample in a reconstruction plane. A holographic propagation operator is applied to the reference complex image, to obtain a plurality of secondary complex images, from which a profile is determined describing the change in an optical feature of the light wave transmuted by the sample along the axis of propagation of the light wave.

Abstract: A method for identifying a state of a cell contained in a sample, including: illuminating the sample using a light source by producing an incident light wave propagating toward the sample; then acquiring, using a matrix-array photodetector, an image of the sample, the sample being placed between the light source and the matrix-array photodetector such that the matrix-array photodetector is exposed to a light wave resulting from interference between the incident light wave and a diffraction wave produced by each cell; applying a numerical reconstruction algorithm to the image acquired by the matrix-array photodetector, to estimate a characteristic quantity of the light wave reaching the matrix-array detector, at a plurality of distances from the matrix-array photodetector. The value of the characteristic quantity, or its variation as a function of distance, allows the state of the cell to be determined from among predetermined states.

Abstract: An analysis system features a confinement device, an optical measurement device, a flow device, a collecting conduit, and an actuation device. The confinement device comprises a measurement chamber, optically transparent first and second measurement surfaces that face each other across a distance that defines a thickness of the measurement chamber, and a flexible membrane that forms a seal with the measurement surfaces to laterally delimit the measurement chamber. When the collecting is sealed with a container, a connection is established that permits a liquid sample to be collected from the container. The optical measurement device emits light towards the chamber and detects light that has been transmitted through it, wherein the flow device causes liquid to flow through the collecting conduit between the container and the measurement chamber. The actuation device varies the thickness.

Abstract: A method for holographic characterization of a particle contained in a sample, based on an image, or hologram, of the sample obtained by an image sensor when the sample is illuminated by a light source. The hologram is the subject of a holographic reconstruction, to obtain a reference complex image, representative of the light wave transmitted by the sample in a reconstruction plane. A holographic propagation operator is applied to the reference complex image, to obtain a plurality of secondary complex images, from which a profile is determined describing the change in an optical feature of the light wave transmuted by the sample along the axis of propagation of the light wave.

Abstract: A method for identifying a state of a cell contained in a sample, including: illuminating the sample using a light source by producing an incident light wave propagating toward the sample; then acquiring, using a matrix-array photodetector, an image of the sample, the sample being placed between the light source and the matrix-array photodetector such that the matrix-array photodetector is exposed to a light wave resulting from interference between the incident light wave and a diffraction wave produced by each cell; applying a numerical reconstruction algorithm to the image acquired by the matrix-array photodetector, to estimate a characteristic quantity of the light wave reaching the matrix-array detector, at a plurality of distances from the matrix-array photodetector. The value of the characteristic quantity, or its variation as a function of distance, allows the state of the cell to be determined from among predetermined states.

Abstract: A process for on-line and in situ counting of cells in a biological culture medium, including a plurality of steps of measuring the capacitance of the medium or a plurality of steps of measuring the conductance of the medium, at distinct frequencies varying within a predetermined range of measurement frequencies. The process includes an extraction of information on the variation of permittivity due to the ?-dispersion in the medium, from the capacitance measurements, and processing of the variation of this information on the variation of permittivity as a function of the frequency, in order to provide information regarding the counting of cells in the medium.

Abstract: Method for biomass determination in a medium, in particular a medium containing biological cells suspended in a conductive fluid, the biomass concentration (X) being obtained from a difference between a first capacitance signal (C?1) of the medium, measured at a first frequency, and a second capacitance signal (C?2) of the medium, measured at a second frequency. The method includes a separate correction of each of the measured signals, based at least on one correction level, the first correction level including a correction of the signals measured in accordance with a model dependent on the conductance of the medium at the first and second frequencies. The invention is useful in biomass measurement systems.

Abstract: A process for on-line and in situ counting of cells in a biological culture medium, comprising the following steps: a plurality of measurements of the capacitance of the medium or a plurality of measurements of the conductance of the medium, at distinct frequencies varying within a predetermined range of measurement frequencies, an extraction of information on the variation of permittivity due to the ?-dispersion in the medium, from the capacitance measurements, and processing of the variation of this information on the variation of permittivity as a function of the frequency, in order to provide information regarding the counting of cells in the medium.

Abstract: Method for biomass determination in a medium, in particular a medium containing biological cells suspended in a conductive fluid, the biomass concentration (X) being obtained from a difference between a first capacitance signal (C?1) of the medium, measured at a first frequency, and a second capacitance signal (C?2) of the medium, measured at a second frequency. The method includes a separate correction of each of the measured signals, based at least on one correction level, the first correction level including a correction of the signals measured in accordance with a model dependent on the conductance of the medium at the first and second frequencies. The invention is useful in biomass measurement systems.