Antibodies and antigens immobilized on magnetic particles of silica as biosensors.

Antibodies and antigens immobilized on silica magnetic particles as biosensors. The present invention provides compositions suitable for the preparation of biosensors consisting of antibodies and antigens immobilized on said magnetic particles magnetic particles improved. The magnetic particles of the invention are particles of iron oxide with a size of 5-30 nm, loaded in basic medium, having a silica coating of 30 to 100 nm thick, characterized in that they have undergone heat treatment 300 to 800 ° C for 1 to 24 hours. The invention also provides a method for the preparation of said magnetic particles. On the other hand, it provides the aforementioned biosensor and a method of preparation thereof. Finally, it provides a method of using such biosensors for identification and quantification of analytes.