Abstract: An apparatus and method for counting nanoparticle probes is disclosed. In one embodiment, quantum dot-tagged proteins on optically transparent membranes or slides are counted. The transparent membranes or slides are loaded onto a stage (e.g., an X-Y stage or X-Y-Z stage), which can automatically reposition the transparent membrane or slides for image capture at varying locations. A microscope can be used for providing a light source to fluoresce the nanocrystals and for providing the magnification needed for image capture. Once one or more images are captured, the nanoparticles can be automatically counted using post-processing software that maintains a total count across multiple images, if desired.

Abstract: An apparatus and method for counting nanoparticle probes is disclosed. In one embodiment, quantum dot-tagged proteins on optically transparent membranes or slides are counted. The transparent membranes or slides are loaded onto a stage (e.g., an X-Y stage or X-Y-Z stage), which can automatically reposition the transparent membrane or slides for image capture at varying locations. A microscope can be used for providing a light source to fluoresce the nanocrystals and for providing the magnification needed for image capture. Once one or more images are captured, the nanoparticles can be automatically counted using post-processing software that maintains a total count across multiple images, if desired.

Abstract: A method for identifying and separating of target biomolecules is disclosed. The method involves contacting a sample with a nanoparticle probe that is capable of specifically binding a target biomolecule. The complex formed by the nanoparticle target biomolecule is separated by electrophoresis using a non-conventional gel composed of a synthetically cross-linked polymer and a gel stabilizer. The nanoparticle probe:target biomolecule complex is detected, thereby identifying the target biomolecule. In certain examples, the nanoparticle probe emits a signal to identify its location. Particular examples of nanoparticle probes are semiconductor nanocrystals, such as quantum dots, which fluoresce at a particular wavelength. Also disclosed is a method of substantially sealing and/or increasing the transparency of a membrane. Such a method includes applying a film to a membrane. Sealing the membrane allows the detection of single nanoparticles.

Abstract: A nanoparticle probe is attached to a substrate to capture targets. The nanoparticle probe includes a specific binding agent that specifically binds to a target biomolecule. The biomolecule can be associated with a cell, for example expressed on the cell's surface, such that the cell is bound to the probe immobilized on the substrate. The nanoparticle probes can be applied to the substrate in a layer, for example in the form of a spot, and multiple spots can be applied to the substrate to form patterns or arrays of the spots on the substrate. The nanoparticle probe presents a binding surface on which oriented specific binding agents (such as antibodies or nucleic acids) can be attached. In particular examples the nanoparticle is spaced slightly from the substrate, for example by a linker, to provide a probe with improved contact with a liquid in which target biomolecules or cells are suspended.