Silicon Nanotube Arrays Deliver mRNA Into Human Stem Cells While Preserving Pluripotency

Key Takeaways

• Nanotube arrays achieve 55‑64% mRNA transfection in hiPSCs
• Pluripotency markers remain >95% after nanoinjection
• Low‑MW poly‑D‑lysine enables mRNA release, boosting efficiency
• ROCK inhibitor pretreatment and delayed Matrigel improve cell contact
• Scalable wafer‑level fabrication supports therapeutic manufacturing

Summary

A team from Monash and Deakin Universities demonstrated that silicon nanotube arrays can deliver functional mRNA into human induced pluripotent stem cells (hiPSCs) with transfection efficiencies between 55% and 64%. By redesigning nanotube geometry, using low‑molecular‑weight poly‑D‑lysine, and adjusting the workflow—ROCK‑inhibitor pretreatment, timed Matrigel coating, and centrifugation—they preserved cell viability (~75%) and pluripotency markers (NANOG, OCT4, SOX2) across passages. The method successfully co‑transfected multiple reporter mRNAs and maintained differentiation potential, offering a non‑viral, integration‑free platform for stem‑cell engineering.

Pulse Analysis

Nanoinjection has emerged as a physical alternative to viral vectors, yet its adoption for human induced pluripotent stem cells has been limited by the cells’ fragility and strict culture requirements. The new study leverages silicon nanotube arrays—hollow, sub‑50 nm tips fabricated by deep reactive‑ion etching—to puncture the membrane and release mRNA directly into the cytoplasm. By pairing this hardware with a chemistry that favors rapid mRNA release, the researchers sidestepped the toxicity and low efficiency that have plagued previous attempts.

Key to the performance jump were three workflow refinements: a ROCK‑inhibitor pretreatment that flattens hiPSCs for tighter nanotube contact, a delayed Matrigel coating that prevents extracellular matrix from sequestering the cargo, and the use of short‑chain poly‑D‑lysine to attract but not trap the negatively charged mRNA. These changes yielded 55‑64% transfection rates, 75% cell viability, and preserved expression of core pluripotency genes across multiple passages. The platform also demonstrated robust co‑delivery of multiple reporter mRNAs, indicating potential for multiplexed gene‑editing or transcription‑factor cocktails.

From a commercial perspective, the wafer‑scale fabrication of silicon nanotube arrays aligns with existing semiconductor manufacturing pipelines, suggesting a clear path to scale‑up for therapeutic cell‑manufacturing. The integration‑free nature of mRNA delivery mitigates regulatory concerns tied to viral vectors, while the high efficiency opens doors for rapid prototyping of disease models, personalized drug screening, and next‑generation cell therapies. As the biotech industry seeks safer, more controllable gene‑delivery technologies, this nanoinjection approach could become a cornerstone for large‑scale stem‑cell engineering.