Quantum Dot-Based Near-Infrared-Sensitive Optoelectronic Biointerface for Neurostimulation

Optoelectronic neural interfaces offer non-genetic and wireless bioelectronic neuromodulation via light. For minimally invasive communication with neurons inside the deep neural structures, transition of optoelectronic neural interfaces to near-infrared (NIR) spectrum is critical. Colloidal quantum dots (QDs) have size-tunable absorption that can cover visible and infrared wavelength spectrum. QDs also have high absorption coefficient that enables fabrication of thin and flexible optoelectronic devices. In this study, we demonstrated a wireless, and flexible QD-based optoelectronic neural interface that can evoke light-induced action potentials in primary hippocampal neurons via 780 nm light in tissue transparency window.¹ We designed a multilayer photovoltaic device architecture with an ultrathin QD layer of 25 nm to generate a safe capacitive ionic current and integrated supercapacitor ruthenium oxide (RuO₂) into the return electrode for improving the photogenerated charge density. Fully solution-processed neural interfaces preserve their functionality after different stability tests and show low in vitro cytotoxicity. Overall, our results disclose the potential of QDs for tether-free bioelectronic photomodulation of neurons in tissue transparency window.<br/><br/>References<br/>(1) Karatum, O.; Kaleli, H. N.; Eren, G. O.; Sahin, A.; Nizamoglu, S. Electrical Stimulation of Neurons with Quantum Dots via Near-Infrared Light. <i>ACS Nano 16, 5, 8233-8243 (</i>2022)