Neural Noise

Non-genetic neuromodulation with graphene optoelectronic actuators

2 min read

  • Non-genetic neuromodulation using graphene optoelectronic actuators has been demonstrated for disease models, stem cell maturation, and biohybrid robotics.1
  • The approach offers an alternative to optogenetics with potential for neural interfaces and neurorobotics.1 1

Weekly enrichment (2026-07-20)

  • GraMOS (Graphene-Mediated Optical Stimulation) is a non-genetic, non-Faradaic platform that uses reduced graphene oxide (rGO) optoelectronic actuators to convert light into capacitive membrane depolarization by charging/discharging the electrical double layer at the graphene–electrolyte–neuron interface, avoiding the genetic modification optogenetics requires; published in Nature Communications 2025 (16:7499) by Molokanova and colleagues.2 3
  • rGO flakes (n > 250) averaged 1.05 ± 0.04 µm lateral size, up to 2.9 ± 0.3 nm height, and 1.46 ± 0.3 µm² surface area; drop-/spray-coated G-coverslips spanned 50–90% optical transmittance, with 70–80% transmittance (~10 ± 2 graphene layers) used for most neuron experiments.2
  • Photocurrents were generated under 480 nm (2.1 mW/mm²), 535 nm (3.7 mW/mm²), and 575 nm (8.3 mW/mm²) illumination; the mechanism is athermal — G-coverslip surface temperature was 23.6 ± 0.03 °C under light versus 23.7 ± 0.04 °C in the dark, and media pH stayed steady across 15–30 min of exposure.2
  • GraMOS required light intensities roughly 100–1000× lower than thermal optocapacitive methods and about three orders of magnitude below photothermal graphene NW-3DFG platforms (which need ~3 kW/cm²), lowering phototoxicity risk.2
  • In 2D hiPSC-derived neurons, light-triggered GraMOS activated nearly 70% of neurons (though only ~10% were mature enough to fire), and neurons cultured on G-coverslips for 3 weeks retained viability (P = 0.00924, one-way ANOVA).3 2
  • Repeated optical stimulation over a 4-week period accelerated maturation of hiPSC-derived neurons and organoids — raising activity, connectivity, and synchronization — with bulk-RNA sequencing showing upregulation of genes for neuronal development/differentiation and synaptic signaling.4 2
  • Acute GraMOS phenotyped Alzheimer’s hiPSC-derived cell models at early stages before spontaneous activity emerges, revealing disease-associated alterations in neuronal activity; reactive-oxygen-species controls used 2 Hz, 1 h/day, 1.9 mW/mm² stimulation for 7 days on 2-month-old organoids.2
  • In a biohybrid-robotics proof-of-concept, GraMOS-activated organoids drove an avoidance maneuver whenever mean firing rate (averaged over ≥8 active electrodes) at least doubled over baseline; the closed loop from detection to execution completed in ≤50 ms and succeeded in 10/10 trials, while light-insensitive control organoids triggered 0/10.2 3

Footnotes

  1. https://news.google.com/rss/articles/CBMiX0FVX3lxTE4xUWVZbVZ3WDNTODlKMDltbVF0dWh3UFF4NXNCcDhvT1pxaFlIc0NvVXJOcGpOVlRkeUI0cHRsRFNmbnJ2NHp0amhjOXFsNVFSb3NyYUQtTG5ubFlUSkRj?oc=5 ↩ ↩2 ↩3

  2. https://www.nature.com/articles/s41467-025-62637-6 ↩ ↩2 ↩3 ↩4 ↩5 ↩6 ↩7 ↩8

  3. https://www.the-scientist.com/light-stimulated-graphene-activates-and-matures-neurons-73295 ↩ ↩2 ↩3

  4. https://www.graphene-info.com/graphene-enabled-optical-stimulation-accelerates-human-brain-organoid ↩

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