Upconversion Nanoparticle-Delivery Flexible Optrodes for Long-Lasting Multichannel Electrophysiology and Transcranial NIR Optogenetics

Near-infrared (NIR) activatable nanoparticles enable
remote, cell-type-specific
manipulation of neuronal activity, whereas flexible microelectrode
arrays (FMAs) facilitate long-term, multichannel recording of neural
signals. Despite the recent development of multifunctional neural
probes, integrating these techniques into a single, minimally invasive
device remains challenging. Here, we present a novel optrode that
combines NIR-activatable upconversion nanoparticles (UCNPs) with FMAs.
The UCNPs and FMAs are coencapsulated in a nanoliter-scale polymer
carrier and delivered into the same brain regions through a single
surgery, ensuring highly spatial congruence between the manipulated
and recorded neuronal populations. Chronically implanted devices enable
simultaneous multichannel recording and transcranial modulation of
opsin-defined neuronal populations over extended periods. The flexibility
and minimal invasiveness of our optrodes provide a powerful tool for
the long-term and spatially precise interrogation of neural circuit
functions.