Development of Dual-Nanopore Biosensors for Detection of Intracellular Dopamine and Dopamine Efflux from Single PC12 Cell.

Detection of neurotransmitters at the single-cell level is essential for understanding the related biological processes and neurodegenerative diseases. We report a dual-nanopore biosensor utilizing a DNA aptamer probe to specifically interact with dopamine, enabling detection of intracellular dopamine and dopamine efflux (extracellular dopamine) in a single pheochromocytoma (PC12) cell. We demonstrate the ability to form an intrapipette electric circuit with the dual-nanopore configuration, which is crucial to achieving both intracellular and extracellular dopamine detection. The sensor allowed rapid detection of dopamine in 10 min with a limit of detection of 0.4 nM. We show the dual-nanopore biosensor was able to monitor single-cell dopamine concentration change under different stimulations. The developed dual-nanopore biosensor represents a novel strategy for time-dependent monitoring of neuron behavior at the single-cell level and potentially can be extended to other platforms for single-cell analysis.

Nanopore biosensor for sensitive and label-free nucleic acid detection based on hybridization chain reaction amplification.

A label-free nanopore biosensor for detection of DNA target is proposed utilizing hybridization chain reaction (HCR) strategy for signal amplification. The DNA target triggered HCR to form large DNA nanostructure inside the nanopore and out the nanopore membrane, which inducing the ionic current decrease effectively due to the blockage of the nanopore. The developed method achieves a desirable sensitivity of 30fM with a wide linear dynamic range from 0.1 to 10pM and demonstrated good application for real sample analysis. This work has great potential to be applied in the early diagnosis of gene-related diseases and provide a new paradigm for label-free nucleic acid amplification strategy in ultrasensitive nanopore biosensor.