Title: High-throughput nanofluidic device for one-dimensional confined detection of single fluorophores,
Abstract: Ensemble averaging experiments may conceal many fundamental molecular
interactions. To overcome that, a high-throughput detection of single molecules
or colloidal nanodots is crucial for biomedical, nanoelectronic, and
solid-state applications. One-dimensional (1D) discrete flow of nanoscale
objects is an efficient approach in this direction. The development of simple
and cost-effective nanofluidic devices is a critical step to realise 1D flow.
This letter presents a nanofabrication technique using
shadow-angle-electron-beam-deposition for a high-throughput preparation of
parallel nanofluidic channels. These were used to flow and detect DNA,
carbon-nanodots, and organic fluorophores. The 1D molecular mass transport was
performed using electro-osmotic flow. The 1D flow behaviour was identified and
analysed using two-focus fluorescence correlation spectroscopy (2fFCS). A range
of flow velocities of single molecules was achieved. The transitions of single
molecules or nanodots through the two foci were quantitatively analysed using
confocal scanning imaging, correlative photon detection, and burst size
distribution analysis. The results suggest an efficient nanofabrication
technique is developed to prepare nanofluidic devices. This first demonstration
of high-throughput nanochannel fabrication process and using 2fFCS-based single
molecule flow detection should have a potential impact on ultra-sensitive
biomedical diagnostics and studying biomolecular interactions as well as
nanomaterials.