Centrifugation-free magnetic isolation of functional mitochondria using paramagnetic iron oxide nanoparticles

Subcellular fractionation techniques are essential for cell biology and drug development studies. The emergence of organelle-targeted nanoparticle (NP) platforms necessitates the isolation of target organelles to study drug delivery and activity. Mitochondria-targeted NPs have attracted the attention of researchers around the globe, since mitochondrial dysfunctions can cause a wide range of diseases. Conventional mitochondria isolation methods involve high-speed centrifugation. The problem with high-speed centrifugation-based isolation of NP-loaded mitochondria is that NPs can pellet even if they are not bound to mitochondria. We report development of a mitochondria-targeted paramagnetic iron oxide nanoparticle, Mito-magneto, that enables isolation of mitochondria under the influence of a magnetic field. Isolation of mitochondria using Mito-magneto eliminates artifacts typically associated with centrifugation-based isolation of NP-loaded mitochondria, thus producing intact, pure, and respiration-active mitochondria.