The present invention relates to a SAMiRNA magnetic nanoparticle complex capable of efficiently delivering double stranded RNA oligonucleotides and magnetic nanoparticle to cells and to a composition comprising the SAMiRNA magnetic nanoparticle complex capable of both diagnosing and treating diseases such as cancer. More particularly the present invention relates to a SAMiRNA magnetic nanoparticle complex wherein a double stranded RNA oligonucleotide polymer structure in which double stranded RNA oligonucleotides and a hydrophilic material and a second hydrophobic material are connected by a simple covalent bond or a linker mediated covalent bond and a magnetic nanoparticle in which a first hydrophobic material is bonded to the surface of a magnetic material are formed into a core. The first hydrophobic material of the present invention performs a hydrophobic interaction with the second hydrophobic material of the double stranded RNA oligonucleotide structure so as to form SAMiRNA magnetic nanoparticle complexes having a uniform size. In addition the hydrophilic material and the second hydrophobic material bonded in the double stranded RNA oligonucleotide structure may improve in vivo stability of the double stranded RNA oligonucleotides. A ligand which is additionally bonded to the structure may deliver a SAMiRNA magnetic nanoparticle complex to a target cell even when a small amount of the ligand is applied and a magnetic material of the magnetic nanoparticle may be used as an imaging agent for diagnosis.
