Entrapment of Magnetic Nanoparticles In A Cross-Linked Protein Matrix Without Affecting The Functional Properties Of The Protein Abstract: Entrapped magnetic nanoparticles in a cross linked matrix of an intended protein, without having the functional properties of the protein affected, and a method for preparing the same is disclosed herein. Further, the use of entrapped magnetic nanoparticles in the protein matrix in diagnostic, immobilization and immunoprecipitation kits is described herein.