Optical sensing and analyte manipulation in solid-state nanopores

The field of nanopore sensing has been gaining increasing attention. Much progress has been made towards biotechnological applications that involve electrical measurements of temporal changes in the ionic current flowing through the pore. But in many cases the electrical signal is restricted by the non-ideal noise components, limited throughput, and insufficient temporal or spatial resolutions. To address these limitations, high-sensitivity optical detection techniques that complement the electrical measurements have been developed. The optical techniques involve high-bandwidth, multicolor and high-throughput measurements. Here we review the recent advancements and developments that have been taking place in the field of optical sensing in solid-state nanopores. We describe the main optical methods used in this field involving total internal reflection and confocal microscopy in addition to sophisticated background suppression strategies. We further present the phenomenon of light induced analyte manipulation at the pore and the contribution of the optical sensing approach to possible nanopore sensing applications such as optical based DNA sequencing using nanopores.