An attractive approach: Biogenic magnetic nanoparticles, so‐called magnetosomes, containing a magnetic iron oxide core enclosed in a protein–lipid membrane, were chemically functionalized with DNA oligonucleotides by using a modular coupling approach. The resulting nanoparticles were used for the assembly of heterostructures with DNA‐modified gold nanoparticles (see TEM image) and as reagents for protein detection