Ferrospheres are buoyant, superparamagnetic iron oxide coated microspheres.
They are available with an amine functionalised surface for the conjugation of antibodies and other ligands. Ferrospheres are the ideal substrate for recovery of low concentration analytes from large sample volumes. On standing they will simply float to the surface or, in a sample containing lots of particulate matter, they can be cleanly separated from debris by centrifugation.
We have developed a magnetic pen that allows the microspheres to be easily manipulated. They can be cleanly retrieved from the surface of the sample and then released into another solution.
The video below shows the magnetic microspheres floating to the surface and then being easily removed with the magnetic pen.
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Some examples of the use of Ferrospheres are described in the following journal articles.
Devlin, R.; Campbell, K.; Kawatsu, K.; Elliott, C. Studies in the Use of Magnetic Microspheres for Immunoaffinity Extraction of Paralytic Shellfish Poisoning Toxins from Shellfish. Toxins 2011, 3, 1-16.
Link to paper
Devlin, R.; Campbell, K.; Kawatsu, K.; Elliott, C. Physical and immunoaffinity extraction of paralytic shellfish poisoning toxins from cultures of the dinoflagellate Alexandrium tamarnse. Harmful Algae, 2011, 10, 542-548.
Link to paper