a-closed-type-wireless-nanopore-electrode-for-analyzing-single

A Closed-Type Wireless Nanopore Electrode for Analyzing Single Nanoparticles

Measuring the intrinsic features of single nanoparticles by nanoelectrochemistry holds deep fundamental importance and has potential impacts in ...

East China University of Science and Technology

An intracellular nanosensor was designed and developed to accurately sense mRNA in living cells without false positive results. This nanosensor consists of gold nanoparticles assembled with recognition sequences and dye-labelled nanoflares. By analyzing both the wavelength shifts and intensity recovery of the scattering spectra, this dual-channel nanosensor could efficiently distinguish and avoid the interference induced by other common substances. This novel dual-channel nanosensor would precisely recognize the target mRNA, and it is promising for further cancer diagnoses.

Dual-channel signals for intracellular mRNA detection via a PRET nanosensor.

Understanding the single molecular protein-protein interaction has great significance in evaluating the affinity of a specific antibody. Herein, the interaction between single α-fetal protein (AFP) and its antibody was monitored via transient ionic current recording by using the antibody functionalized nanopore sensors. More importantly, the kinetic evaluation was performed at the single molecule level to determine the dissociation constant of this interaction. This method enables the monitoring of the kinetic antigen-antibody interaction in their heterogenetic state without any labelling. Our results provided new insights into the evaluation of the antibody's binding affinity and more into the development of immunoassays for diagnostics.

Single antibody-antigen interactions monitored via transient ionic current recording using nanopore sensors.

Here, we show a designed solid-state nanopore sensor for the direct sensing and quantification of prostate-specific antigen (PSA) as cancer biomarker in serum without any pretreatment. This nanopore technique provides a convenient, fast, and low-cost quantification of cancer biomarkers in clinical samples.

Direct sensing of cancer biomarkers in clinical samples with a designed nanopore.

Analysis of nicotinamide adenine dinucleotide (NAD/NADH)-modified electrodes is important for in vitro monitoring of key biological processes. In this work, time-of-flight secondary ion mass spectrometry (ToF-SIMS) was used to analyze NAD/NADH-modified gold electrodes. Interestingly, no obvious characteristic peaks of nicotinamide fragment could be observed in the mass spectra of NAD/NADH in their neutral sodium pyrophosphate form. However, after acidification, the characteristic peaks for both NAD and NADH were detected. This was due to the suppression effect of inner pyrophosphoric salts in both neutral molecules. Besides, it was proved that the suppression by inner salt was intramolecular. No obvious suppression was found between neighboring molecules. These results demonstrated the suppression effect of inner salts in ToF-SIMS analysis, providing useful evidence for the study of ToF-SIMS ionization mechanism of organic molecule-modified electrodes. Graphical Abstract ᅟ.

Investigation of the Ionization Mechanism of NAD/NADH-Modified Gold Electrodes in ToF-SIMS Analysis.

Nanopore sensing is a powerful single-molecule method for DNA and protein sequencing. Recent studies have demonstrated that aerolysin exhibits a high sensitivity for single-molecule detection. However, the lack of the atomic resolution structure of aerolysin pore has hindered the understanding of its sensing capabilities. Herein, we integrate nanopore experimental results and molecular simulations based on a recent pore structural model to precisely map the sensing spots of this toxin for ssDNA translocation. Rationally probing ssDNA length and composition upon pore translocation provides new important insights for molecular determinants of the aerolysin nanopore. Computational and experimental results reveal two critical sensing spots (R220, K238) generating two constriction points along the pore lumen. Taking advantage of the sensing spots, all four nucleobases, cytosine methylation and oxidation of guanine can be clearly identified in a mixture sample. The results provide evidence for the potential of aerolysin as a nanosensor for DNA sequencing.

Mapping the sensing spots of aerolysin for single oligonucleotides analysis.

The realization of the reversible inter-conversion between NADH and NAD+ is a long-term challenge in biological and energy-related chemistry. Here, we achieve the electrochemical reversible redox of NAD+/NADH derivatives by the functionalization of a gold electrode with a specially designed NAD+ derivative, and the electrochemical redox products are characterized by time-of-flight secondary ion mass spectrometry (ToF-SIMS).

Article	Year
Dual-channel signals for intracellular mRNA detection via a PRET nanosensor. Chemical communications (Cambridge, England)\| PubMed ID: 28650007	2017
Single antibody-antigen interactions monitored via transient ionic current recording using nanopore sensors. Chemical communications (Cambridge, England)\| PubMed ID: 28721409	2017
Direct sensing of cancer biomarkers in clinical samples with a designed nanopore. Chemical communications (Cambridge, England)\| PubMed ID: 28990601	2017
Investigation of the Ionization Mechanism of NAD/NADH-Modified Gold Electrodes in ToF-SIMS Analysis. Journal of the American Society for Mass Spectrometry\| PubMed ID: 29869326	2018
Mapping the sensing spots of aerolysin for single oligonucleotides analysis. Nature communications\| PubMed ID: 30026547	2018
Reversible redox inter-conversion of biologically active NAD/NADH derivatives bound to a gold electrode: ToF-SIMS evidence. Chemical communications (Cambridge, England)\| PubMed ID: 30457615	2018

Yi-Tao Long

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