New Technique Enables Cytoplasmic Transfer Across Cell Barriers

Cells interact dynamically, exchanging proteins, genetic material, and organelles to regulate tissue development, stress responses, and repair. Tumor cells in cancers, for example, take up mitochondria from neighbors to support growth, with similar processes implicated in aging. Yet despite advances in gene-editing and molecular-targeting technologies, tools for directly and reliably altering the cytoplasmic composition of living cells have been lacking.

Previous approaches faced obstacles in both extraction and delivery. Detergent or enzyme-based lysis destroys cells completely. Ultrasound and other physical methods require precise tuning to avoid biomolecule damage, making them labor-intensive. Delivery remains problematic too—lipid carriers work only for small molecules, viral vectors are expensive, and microinjection cannot scale effectively. No existing method supports controlled, efficient cytoplasmic transfer while maintaining cell viability.

Now, a Waseda University team led by Professor Takeo Miyake has developed a nanotube membrane-based injector to address these issues, publishing their work in Small Science. The system uses a thin gold membrane featuring vertically aligned nanotubes positioned on a glass tube. When gently pressed against cultured cells, the nanotubes penetrate the phospholipid bilayer without major harm. By controlling air pressure within the tube, researchers extract cytoplasmic contents from donor cells, store them briefly during repositioning, and deliver them to recipient cells with microliters of buffer.

Experiments using fluorescent dyes and protein assays showed pressure-dependent extraction worked reliably. Fine-tuning nanotube diameter, density, and pressure achieved 95% cell viability and over 90% transfer efficiency. Confocal microscopy confirmed dozens of fluorescent-tagged mitochondria transferred per cell remained functional, as recipient cells generated much higher ATP levels than controls.

"This technology establishes a new paradigm for cell manipulation—transforming cells not by genetic modification but by reconstructing intracellular composition itself," states Professor Miyake. He adds, "Directly transferring healthy mitochondria or cytoplasmic components into target cells is particularly relevant for regenerative medicine, where therapeutic cells often suffer from reduced metabolic activity or functional heterogeneity after isolation and expansion. By restoring or augmenting mitochondrial function without genetic modification, the technology offers a new strategy to improve cell quality prior to transplantation."