• FMRCs enable efficient mitochondrial transfer via magnetic-force-assisted membrane fusion, overcoming limitations of conventional methods.
• Transplantation of intact mitochondrial networks from FMRCs restores mitochondrial function in cells with mtDNA depletion or deletion.
• Exogenous mitochondria stably and predominantly reside in recipient cells, as confirmed by SNP tracing and qPCR.
• FMRC-mediated mitochondrial transplantation reduces mtDNA heteroplasmy by stimulating autophagy and clearance of defective mitochondria.