A flow cytometer can include: at least one light emitter configured to emit light in a light path; a rectangular flow cell having flow cell width that is substantially lateral to the light path and a flow cell depth that is longitudinal to the light path, wherein the light path has an interrogation width at the flow cell that is narrower than the flow cell width; and a spherical reflector positioned adjacent to the rectangular flow cell and having a concave reflective surface that has a reflective direction that is positioned substantially orthogonal with the light path such that reflected light is reflected along a reflected path that is substantially orthogonal with the light path. At least one light absorbing member is positioned at least partially around the reflected path to absorb reflected light at an angle to the reflected path.

The invention provides an optical particle sensor (1) comprising: at least one light source (2, 2r, 2g, 2b) configured to emit light rays (20), at least one channel (3) intended to receive a fluid transporting at least one particle (30), and to at least partially receive the light rays (20) emitted by the at least one source (2, 2r, 2g, 2b), such that said light rays (20) are partially scattered by the at least one particle (30), at least one photodetector (4) capable of receiving said scattered light rays (20),
said sensor (1) being characterised in that the at least one source (2, 2r, 2g, 2b) has an emission face (21) facing one side (D) of the sensor and in that the at least one photodetector (4) has a receiving face (41) facing the same side (D) of the sensor (1), such that the light rays received by the at least one photodetector are light rays (20b) backscattered by the at least one particle (30), for at least 90% of them.

A method for measuring concentrations of blood cell components is provided. The method comprises: obtaining a blood sample from a subject, the blood sample comprising at least one of red blood cells (RBCs), white blood cells (WBCs), and platelets (PLTs); mixing the blood sample with a non-lysing aqueous solution to form a sample mixture comprising a predetermined tonicity; passing the sample mixture through a flow cell; emitting light towards the flow cell; measuring at least one of an amount of light absorbed by the RBCs to obtain an RBC absorption value, an amount of light scattered by WBCs to obtain a WBC scatter value, and an amount of light scattered by PLTs to obtain a PLT scatter value; and determining a concentration of at least one of the RBCs, WBCs, and PLTs present in the sample mixture.

Light detection systems are provided. Aspects of the light detection systems include first and second light receivers in fixed positions relative to each other, a plurality of wavelength separators configured to pass light from the first and second light receivers having a predetermined spectral range, and a plurality of light detection modules. Baseplates having a stage for mounting a light receiver, a plurality of recesses for fixing a plurality of light detection modules in rigid alignment relative to the stage, and a heat dissipation opening positioned within each recess are also provided. In addition, particle analysis systems, methods and kits for practicing the invention are disclosed.

Described herein are apparatuses for analyzing an optical signal decay. In some embodiments, an apparatus includes: a source of a beam of pulsed optical energy; a sample holder configured to expose a sample to the beam; a detector comprising a number of spectral detection channels configured to convert the optical signals into respective electrical signals; and a signal processing module configured to perform a method. In some embodiments, the method includes: receiving the electrical signals from the detector; mathematically combining individual decay curves in the electrical signals into a decay supercurve, the supercurve comprising a number of components, each component having a time constant and a relative contribution to the supercurve; and numerically fitting a model to the supercurve.

A method for evaluating a biological material for unassociated virus-like particles virus size having a particular epitope uses a fluorescent antibody stain specific for binding with the epitope and a fluid sample with the virus-size particles and fluorescent antibody stain is subjected to flow cytometry with identification of fluorescent emission detection events indicative of passage through a flow cell of a flow cytometer of unassociated labeled particles of virus size including such a virus-like particle and fluorescent antibody stain.

A system for characterizing at least one particle from a fluid sample is disclosed. The system includes a filter disposed upstream of an outlet, and a luminaire configured to illuminate the at least one particle at an oblique angle. An imaging device is configured to capture and process images of the illuminated at least one particle as it rests on the filter for characterizing the at least one particle. A system for characterizing at least one particle using bright field illumination is also disclosed. A method for characterizing particulates in a fluid sample using at least one of oblique angle and bright field illumination is also disclosed.

Disclosed herein are systems, methods, and techniques for optical detection of analytes (e.g., biomarkers or other objects) using a liquid-core waveguide in which the analytes are suspended in a high-index liquid inside a liquid channel of the waveguide. The term “high-index” may indicate a refractive core index of the carrier liquid that is higher than or equal to that of one or more surrounding cladding layer(s) (e.g., ethylene glycol liquid inside a glass channel). In some embodiments, a method includes illuminating, by a light-source, one or more particles in a liquid-core waveguide, wherein the liquid-core waveguide comprises a first cladding layer having a first index of a refraction, and a hollow core comprising a liquid inside the hollow core, wherein the liquid has a second index of refraction higher than the first index of refraction; and detecting, by a detector, light emitted from the one or more particles.

A hydrodynamic focusing device comprises first and second flow channels; a wall at least partially defining an envelopment region connected in-line between the first and second flow channels which collectively define a flow direction extending therethrough; and a chimney comprising a body and a sample fluid inlet, extending from the wall and into the envelopment region. The sample fluid inlet faces at least partially perpendicular to the flow direction in the envelopment region, such that the sample fluid inlet is configured to supply a sample fluid into the envelopment region in a direction that is at least partially perpendicular to the flow direction. The body and the sample fluid inlet each have an elongate profile which has a rounded leading edge facing the first flow channel and opposing long edges connecting the leading and trailing edges and tapered towards the trailing edge.

Described herein are apparatus and methods for orthographic imaging of particles. Particularly, a method to obtain contact-free images of aerosol particles with digital holography from three orthogonal directions is described and demonstrated. Diode lasers of different wavelengths simultaneously illuminate free flowing particles to form holograms on three sensors. Images of the particles are reconstructed from the holograms and used to infer the three-dimensional structure of single spherical particles or clusters of sphere-like particles. The apparatus employs inexpensive components and requires no lenses to achieve the imaging, which gives it a large sensing volume and simple design.