Researchers from Harvard have developed a ultrathin soft bioelectronic mesh that integrates into embryonic neural tissue to longitudinally monitor single-cell brain activity with millisecond resolution. This mesh conforms seamlessly to the neural plate as it transforms into a three-dimensional brain during development, without disrupting normal growth or function. In axolotl models, the device records and even stimulates regeneration processes. This technology offers unprecedented access to neural circuit formation and neurodevelopmental disorder mechanisms in vivo, as reported in Nature in 2025.