A light-driven nanopipette ion pump for probing subcellular oxygen levels

The rich interplay of light-bio-matter taking place in the nanoscale has recently seen a dramatic increase in exploration. Here, we have devised a biomimetic, visible-light-driven, single-nanopore ion pump by confining the photoelectric heterojunction of lead sulfide quantum dots (PbS QDs) and poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) within the orifice of a nanopipette. This established a light-fueled trans-pore potential originating from a charge gradient, resulting in unidirectional ionic migration and thus continuous generation of ionic current passing through the asymmetric nanopore. As it was oxygen (O2) 2 ) sensitive and fully compatible with single-cell studies, we implemented it toward in situ photo- electrochemical probing of subcellular O2 2 levels inside single living cells. This allowed us to study spatiotemporal intracellular O2 2 distribution and mitochondrial respiration-associated chemotherapeutics. The proposed light-driven nanopipette iontronic device will significantly advance future single-nanopore and single-cell studies.