A pipette tip extension attachable to a pipette tip is disclosed. The pipette tip extension has a proximal end, a distal end, and an exterior wall extending between the proximal end and the distal end. The exterior wall has an outer side and an inner side and forms at the proximal end a reception aperture for inserting a pipette tip. The pipette tip extension also has a bottom at the distal end, an inner cavity enclosed by the inner side of the exterior wall and the bottom, and one or more distance elements arranged at the inner side of the exterior wall and protruding into the inner cavity.

A pipette tip extension attachable to a pipette tip is disclosed. The pipette tip extension has a proximal end, a distal end, and an exterior wall extending between the proximal end and the distal end. The exterior wall has an outer side and an inner side and forms at the proximal end a reception aperture for inserting a pipette tip. The pipette tip extension also has a bottom at the distal end, an inner cavity enclosed by the inner side of the exterior wall and the bottom, and one or more distance elements arranged at the inner side of the exterior wall and protruding into the inner cavity.

A variety of devices, systems, kits, and methods are provided for separating or enriching circulating tumor cells in a biological sample such as whole blood. In some aspects, the devices are multi-stage devices including at least a filtering stage, and two separation stages for ferrohydrodynamic separation of magnetically labelled white blood cells and for marker-independent and size-independent focusing of magnetically labeled particles so as to separate or enrich unlabeled rare cells in the biological sample. The devices and methods are, in some aspects, capable of high throughput in excess of 6 milliliters per hour while achieving high separation (>97%) of the unlabeled rare cells.

A variety of devices, systems, kits, and methods are provided for separating or enriching circulating tumor cells in a biological sample such as whole blood. In some aspects, the devices are multi-stage devices including at least a filtering stage, and two separation stages for ferrohydrodynamic separation of magnetically labelled white blood cells and for marker-independent and size-independent focusing of magnetically labeled particles so as to separate or enrich unlabeled rare cells in the biological sample. The devices and methods are, in some aspects, capable of high throughput in excess of 6 milliliters per hour while achieving high separation (>97%) of the unlabeled rare cells.

Devices, methods, and systems are provided for extracting particles from a ferrofluid. Such methods may comprise receiving a flow of ferrofluid comprising target particles and background particles and generating a first, focusing magnetic field to focus the target particles towards a capture region. The capture region may capture the target particles and a plurality of background particles. A second, defocusing magnetic field may be configured to remove background particles from the capture region. A detector may be used to detect the target particles bound to the target region.

Devices, methods, and systems are provided for extracting particles from a ferrofluid. Such methods may comprise receiving a flow of ferrofluid comprising target particles and background particles and generating a first, focusing magnetic field to focus the target particles towards a capture region. The capture region may capture the target particles and a plurality of background particles. A second, defocusing magnetic field may be configured to remove background particles from the capture region. A detector may be used to detect the target particles bound to the target region.

A pipette tip extension attachable to a pipette tip having a proximal end, a distal end, and an exterior wall extending between the proximal end and the distal end is disclosed. The exterior wall has an outer side and an inner side and forms at the proximal end a reception aperture for inserting a pipette tip, and at the distal end a dispense aperture. The pipette tip extension further has an inner cavity, a distance element connected to the inner side of the exterior wall, and a constriction element.

Method for detecting the presence or absence of a biological or chemical substance in a particular sample mixed with a suspension with functionalized magnetic particles, comprising: providing a light source and detector, providing a constant magnetic force perpendicular to the light's propagation direction by applying a constant magnetic field gradient, and with an absolute value which is higher than 0.1 T and measuring the change of the magnetic particle's suspension transparency versus time and comparing it with the time-variation in absence of the targeted biological or chemical substance. The method of the invention allows monitoring the transparency irrespective of the emitted wavelength and particle's optical properties.

Method for detecting the presence or absence of a biological or chemical substance in a particular sample mixed with a suspension with functionalized magnetic particles, comprising: providing a light source and detector, providing a constant magnetic force perpendicular to the light's propagation direction by applying a constant magnetic field gradient, and with an absolute value which is higher than 0.1 T and measuring the change of the magnetic particle's suspension transparency versus time and comparing it with the time-variation in absence of the targeted biological or chemical substance. The method of the invention allows monitoring the transparency irrespective of the emitted wavelength and particle's optical properties.

Provided is a magnetic filtration apparatus with a simple structure for permitting easy and effective discharge of magnetic substances from the inside of a flow passage to its outside, the magnetic substances being captured by attraction from a liquid to be treated by magnetic separation. The magnetic filtration apparatus includes a treatment container 12 having an inlet 26 and outlet 28 of the liquid, and a discharge port 36 of the separated magnetic substances. A magnetic apparatus 20 attached around the treatment container 12 attracts the separated magnetic substances to an inner wall of the treatment container 12, while cancellation of the effect of the magnetic field generated by the magnetic apparatus 20 allows the attracted magnetic apparatus to flow into a detachable collecting container 14 positioned below the treatment container 12, due to the gravity, through a communication passage 15.