Abstract: Presented herein is a method and devices for identifying biological molecules and cells labeled by small magnetic particles and by optically active dyes. The labeled molecules are typically presented in a biological fluid but are then magnetically guided into narrow channels by a sequential process of magnetically trapping and releasing the magnetic labels that is implemented by sequential synchronized reversing the magnetic fields of a regular array of patterned magnetic devices that exert forces on the magnetic particles. These devices, which may be bonded to a substrate, can be formed as parallel magnetic strips adjacent to current carrying lines or can be substantially of identical structure to trilayered MTJ cells. Once the magnetically labeled molecules have been guided into the appropriate channels, their optical labels can be detected by a process of optical excitation and de-excitation. The molecules are thereby identified and counted.

Abstract: The invention relates to a system and a method for the detection of target components (102) in a sample with the help of indicator particles (101) distributed in said sample. The distance (d) between indicator particles (101) and a contact surface (112) is determined after the target components could bind to the contact surface and/or the indicator particles. Thus it is possible to detect how many target components (102) are bound without a need for a binding between indicator particles (101) and contact surface (112). Optionally the indicator particles (101) can be affected by a modulated force, e.g. via an electromagnet (141). The determination of the distance (d) between indicator particles (101) and contact surface (112) may for example be achieved by frustrated total internal reflection, measurement of magnetic fields, or FRET.

Abstract: The present invention provides simple and inexpensive assays for the detection of virtually any analyte in any sample that is in liquid form or that can be solubilized. The assays utilize the fluid dynamics of drop evaporation whereby soluble materials, including analytes and particles binding thereto, are drawn to the edge of the drop and ultimately form a concentrated residual ring. The presence or absence of certain reagents can then be detected through a number of different approaches.

Abstract: A method of detecting a target within a population of molecules comprising: contacting a plurality of labeled probe molecules with the population of molecules potentially containing a target of the probe molecules; acquiring a probe specific signal emitted by said labeled probe molecules that bound to said target together with a background signal; preferentially modulating said probe specific signal by at least one of modulating said acquisition and modulating an emission of said probe specific signal; and detecting said probe specific signal over said background signal using said preferential modulation.

Abstract: The invention provides assay particles useful, for example, for detecting analytes and binding molecule interactions. One type of assay particle includes a core portion encased by a shell portion, wherein the shell portion comprises an inorganic phosphor that binds selectively to a target molecule. Another type of an assay particle includes a core portion encased by a shell portion, and a coat portion covering the shell portion, wherein the coat portion comprises an inorganic phosphor that binds selectively to a target molecule. A further type of assay particle includes a core portion encased by a shell portion, and a coat portion covering the shell portion, wherein the coat portion comprises an inorganic phosphor and a target selective binding moiety, and wherein the assay particle is buoyant in aqueous media.

Abstract: A particle detector apparatus for optically ascertaining a number of particles arranged on a surface of, for example, a particle filter. The particle detector apparatus includes a light source, an optical focusing device, a spatially resolving light detector and an evaluation device. The light source emits source light onto the surface. The optical focusing device focuses image light that is emitted from the surface in response to the source light onto the spatially resolving light detector. The spatially resolving light detector includes light sensors that measure brightness values based on the image light, such that the light detector produces image data based on the brightness values delivered by the light sensors. The evaluation device then ascertains the number of particles based on the image data.

Abstract: The ability to levitate, to separate, and to detect changes in density using diamagnetic particles suspended in solutions containing paramagnetic cations using an inhomogeneous magnetic field is described. The major advantages of this separation device are that: i) it is a simple apparatus that does not require electric power (a set of permanent magnets and gravity are sufficient for the diamagnetic separation and collection system to work); ii) it is compatible with simple optical detection (provided that transparent materials are used to fabricate the containers/channels where separation occurs; iii) it is simple to collect the separated particles for further processing; iv) it does not require magnetic labeling of the particles/materials; and v) it is small, portable.

Abstract: A sample preparation device and associated method is provided for preparing samples according to an assay protocol. A cell deposition module deposits a sample on each a plurality of assay devices supported by a support device. An epitope retrieval module deposits a reagent on each of the samples. Each of the samples is brought to a selected temperature. A heating device, corresponding to each of the assay devices, directly interacts with the corresponding assay device may be used to heat each assay device to the selected temperature, in conjunction with the epitope retrieval module depositing the reagent on each of the samples. A staining module deposits a staining reagent on each of the samples, and removes excess staining reagent. The staining, epitope retrieval, and cell deposition modules cooperate with the support device and heating devices to form a unitary sample preparation device.

Abstract: Method for detecting a material of interest, usually an antibody or an antigen on a red blood cell, in a liquid, by observing the potential antigen/antibody reaction products in a novel way. Reaction products are deposited on a magnetic substrate and will exhibit different properties depending upon whether or not the antigen/antibody reaction has taken place. An antigen/antibody reaction product adheres tenaciously to itself and the substrate while the deposit of any unreacted magnetically tagged material is weakly adhering and easily disrupted and dislodged under a disruptive force which would be insufficient to dislodge the reacted deposit. This difference in cohesive property provides the means by which a positive result is distinguished from a negative result.

Abstract: The present invention relates to a method for purifying biomolecules or for analyzing whether an aqueous phase contains biomolecules by means of magnetic separation. The invention further relates to uses, to devices, and to kits that relate to the method according to the invention.

Abstract: This invention provides nanometer-sized fluorescent magnetic particles and processes of making them. The nanoparticle has a core particle comprising a magnetic material and a fluorescent material, and the particle size is less than about 1 micrometer. The nanoparticles can be coated with an inorganic or organic layer and can be surface-modified. The nanoparticles can be used in many biological assays.

Abstract: Sensor assay methods for detecting the presence of an analyte in a sample are provided. Aspects of the methods include providing a sensor, e.g., a proximity sensor, in contact with an assay composition that includes a sample and a proximity label. Next, a capture probe configured to bind to the proximity label and the analyte is introduced into the assay composition to produce a labeled analyte. Following capture probe introduction, a signal is obtained from the sensor to detect the presence of the labeled analyte in the sample. Also provided are sensor devices, including hand-held devices, and kits that find use in practicing the subject methods.

Abstract: Particle populations and assays are provided which have varying amounts of magnetic material and varying particle concentrations among different subsets of particles. In particular, the particle populations and assays include at least two particle sets with distinct sums of particles which are inversely related to the magnetic material concentration comprising each of the particles within the two particle sets, respectively. A method for processing an assay having such particle sets includes routing the assay in proximity to an imaging plane within a static imaging optical analysis system and generating a magnetic field in proximity to the imaging plane. The magnetic field is sufficient to attract and immobilize a ratio of particles from the at least two discrete particle sets that is different from the ratio of particles comprising the at least two discrete particle sets in the assay as the assay is introduced into the static imaging optical analysis system.

Abstract: The present invention relates to compositions, assay devices, kits and methods for detecting the presence, amount and/or activity of an analyte in a sample. In particular, the present invention relates to the detection of enzymes. The present invention also relates to methods of diagnosing diseases associated with dysregulation of enzymes, screening for modulators of enzymatic activity, candidate antimicrobial peptides and toxins.

Abstract: Polymer particles are provided which contain fluorescent molecules with high presence ratio in a polymer layer thereof and a method for preparing thereof. Polymer particles are swelled in a non-aqueous solution excluding exclusively water preferably promotes selling of the polymer layer and transfer of the fluorescent molecules to the polymer layer could not protected by water molecules such that much more fluorescent molecule may be introduced into inside of the polymer layer. Furthermore, since the water is added to the reaction system prior to evaporation removal of the non-aqueous solvent, dry-up of the polymer particles is prevented by the water remained in the reaction system and the polymer particles including fluorescent molecules with high presence ratio of the fluorescent molecules preferably keep high dispersibility using the above described procedures.

Abstract: The present invention discloses a method for separating nanoparticles with a controlled number of active groups is disclosed. First, a plurality of nanoparticles are provided, wherein the surface of the nanoparticle comprises a plurality of first active groups. Next, a plurality of functional ligands are provided, wherein the functional ligand comprises at least one second active group and at least one third active group. Then, a binding process is performed to bind the nanoparticle with the functional ligand, wherein the first active group connects with the second active group. After the binding process, a separation process is performed to isolate a plurality of nanoparticles with a controlled number of the third active groups. The controlled number is integers from 0 to 10.

Abstract: A Raman spectroscopy technique allows an analyte, a paramagnetic particle, and a spectral enhancement particle to combine in solution and for the combination product to be localized by a magnetic field for analysis. The spectral enhancement particle may be comprised of an active SERS metal particle with or without a material coating. The spectral enhancement particle may function as a reporter for the presence of the analyte or merely increase the magnitude of the Raman spectrum of the analyte. The technique is applicable to both immunoassays and chemical assays. Multiple spectral enhancement particle reporters may be measured in a single assay that can detect multiple analytes using the SERS effect.

Abstract: Methods for separating, in a continuous, multizone fluid medium, cells, particles, or other molecules of interest (MOI) from associated or contaminating unwanted materials not of interest (MNOI). The invention involves forced movement of MOI into certain zones having properties which deter the entry of unwanted materials. Differential movement of MOI and MNOI occurs by active counterforces that move MNOI but not MOI. MOI are tagged with magnetic particles and moved with a magnetic field through a fluid, or zones, of higher specific gravity that prevents, by flotation counterforce, unwanted less dense materials from entering. Surfaces specifically coated with reactants are reactive with the MOI in the tagged magnetic particle complex and of buoyant or other forces are used to remove any unbound material from the surface before reading.

Abstract: Disclosed herein are methods, kits and systems for signal amplification that can be used for many analytes. For example, a method of detecting an analyte in a sample includes contacting the sample containing the analyte with a detecting agent, wherein the detecting agent contains a specific binding agent that binds the analyte and zinc nanoparticles wherein the zinc nanoparticles and specific binding agent are coupled together; exposing the analyte bound to the specific binding agent which is coupled to the zinc nanoparticles to an acidic condition to release zinc ions from the zinc nanoparticles; contacting the released zinc ions with an indicator to generate a signal; and detecting the signal. The disclosed bioassay can be used in clinical and non-clinical settings. For example, the method can be used for clinical diagnosis, prognosis, and/or treatment-effectiveness or for testing for the presence of a substance like biological or chemical agents.

Abstract: A method of detecting a target analyte in a sample, including executing electrowetting-mediated droplet operations and thereby: combining one or more immunoassay reagent droplets comprising magnetically-responsive beads having affinity for the target analyte with one or more sample droplets potentially comprising the target analyte to yield a first combined droplet; beginning with the combined droplet, effecting a droplet-based washing protocol to wash the magnetically-responsive beads to yield a first washed droplet comprising the washed magnetically responsive beads; and combining the droplet comprising the washed magnetically responsive beads with a droplet comprising a reporter molecule having affinity for target analyte captured on the magnetically-responsive beads to yield a second combined droplet; beginning with the second combined droplet, effecting a droplet-based washing protocol to wash the magnetically-responsive beads to yield a second washed droplet comprising the washed magnetically responsive