Spinal cord injury causes lasting disability because neurons rarely regenerate and scar tissue blocks regenerating fibres. Current approaches use electrical stimulation to encourage transplanted stem cells to form neurons, but they typically need implanted electrodes and the cells can fail to survive or integrate. To address these limits, a Zurich team reported in Nature Materials a microrobotic approach that combines therapeutic progenitor cells with magnetoelectric nanoparticles.
Their biohybrid microrobot, called an NPCbot, pairs living neural progenitor cells derived from induced pluripotent stem cells with engineered nanoparticles that have two functional layers: an inner layer that responds to magnetic fields and an outer layer that converts that response into electrical impulses. Production takes place on a lab-on-a-chip surface; cells are trapped in a central reservoir, nanoparticles are added and the components bind, producing ready microrobots in a short time. Parallel lab-on-a-chip systems allow scaling to the numbers needed for studies.
In experiments the NPCbots were injected into injured spinal cords and external electromagnetic fields were applied. In zebrafish larvae, treated animals showed nearly normal swimming and exploratory behaviour within three days. In mice with completely severed spinal cords, nerve reconnection at the injury and marked improvements in gait, stride length, coordination and exploratory behaviour appeared after 28 days. The treatment was well tolerated with no clear adverse effects or immune reactions. The particles appear stable thanks to a barium titanate coating, but further studies must clarify how they are degraded or excreted over time.
The researchers say more work is required before human trials: they must determine which magnetic fields and stimulation durations work best in people. They also note that the reproducible, scalable lab-on-a-chip production could be adapted for cardiology, oncology, wound healing and other targeted regenerative therapies, potentially making such treatments safer and more controllable.
Difficult words
- regenerate — grow back or repair after tissue damage
- progenitor cell — immature cell that can make specific cell typesprogenitor cells
- magnetoelectric — material that converts magnetic signals into electrical signals
- lab-on-a-chip — small device that performs laboratory steps automatically
- biohybrid — combines living cells with engineered components
- gait — manner or pattern of walking
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- What concerns arise from the nanoparticles' long-term stability and how could researchers address them?
- How might lab-on-a-chip production make regenerative therapies safer and more controllable?
- What steps should researchers take before testing this treatment in people, based on the article?
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