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

Aggregation-induced emission (AIE) as a unique photophysical process has been intensively explored for their features in fields from optical sensing, bioimaging to optoelectronic devices. However, all AIE luminogens (AIEgens) hardly recover into the initial dispersed state after illuminating at the ultimate aggregated state, which limits AIEgens to achieve reversible sensing and reproducible devices. To real-time manipulate the emission of AIEgen, here we take the advantage of confined space in the quartz nanopore to achieve a nanopore-size-dependent restriction of AIEgens for reversible conversions of "on-to-off" and "off-to-on" emission. By electrochemically manipulating 26 fL AIEgen solution inside nanopore confinement, AIE illuminates while moves along nanopore from the constricted tip to inside cavity at a velocity of 1.4-2.2 μm s, and vice versa. We further apply this dynamic manipulation for a target delivery of AIEgen into single cells, which opens up new possibility to design powerful and practical AIE applications.

Manipulating and visualizing the dynamic aggregation-induced emission within a confined quartz nanopore.

Wild-type aerolysin (AeL) nanopores allow direct single nucleotide discrimination of very short oligonucleotides (≤10 nt) without labelling, which shows great potential for DNA sensing. To achieve real applications, one major obstacle of AeL is its poor capture ability of long single-stranded DNA (ssDNA, >10 nt). Here, we have proposed a novel and robust strategy for the electrostatic focusing of long ssDNA into a lithium-chloride (LiCl)-active AeL. By using this method, for the first time we have demonstrated AeL detection of ssDNA longer than 100 nt. Due to screening more negative charges, LiCl improves AeL capture ability of long ssDNA ( 60 nt) by 2.63- to 10.23-fold compared to KCl. Further calculations and molecular dynamics simulations revealed that strong binding between Li and the negatively charged residue neutralized the AeL, leading to a reduction in the energy barrier for ssDNA capture. These findings facilitate the future high-throughput applications of AeL in genetic and epigenetic diagnostics.

A lithium-ion-active aerolysin nanopore for effectively trapping long single-stranded DNA.

Multidrug-resistant bacteria are a great concern and a problem that must be addressed. Extended-spectrum β-lactamases are a common defence mechanism of bacteria to make β-lactam (BL) antibiotics ineffective. β-Lactamase inhibitors (BLIs) are consequently designed and are often clinically prescribed with a BL antibiotic to hinder degradation. Current studies focusing on how BL antibiotics or BLIs interact solely with the bacterial outer membrane nanopores (porins) on reaching the periplasmic side using a nanopore-based sensing technique. In electrochemical studies, the bias voltage allows real-time monitoring of BL antibiotics, BLIs and their mixture through the porin pathway at the single-molecule level. Here we consider the most abundant membrane protein from Escherichia coli (i.e. OmpF), purify and reconstitute the membrane protein in an artificial lipid bilayer and then study its ex vivo electrochemical behaviour. We show the piperacillin/tazobactam mixture interacts with OmpF, whereas the substrate interacts under the maximum bandwidth. The power spectrum analysis of the ionic current trace demonstrates the ampicillin/sulbactram mixture requires more energy than ampicillin alone to pass through the porin pathway. Our results demonstrate that clinically relevant combinations (e.g. piperacillin/tazobactam and ampicillin/sulbactam) interact more strongly with OmpF than either the BL antibiotic or the BLI alone. We suggest a quick and relatively cheap screening method to test the ability of BL antibiotics/BLIs to cross the bacterial cellular membrane.

Article	Year
Manipulating and visualizing the dynamic aggregation-induced emission within a confined quartz nanopore. Nature communications\| PubMed ID: 30194303	2018
A lithium-ion-active aerolysin nanopore for effectively trapping long single-stranded DNA. Chemical science\| PubMed ID: 30746084	2019
Real-time monitoring β-lactam/β-lactamase inhibitor (BL/BLI) mixture towards the bacteria porin pathway at single molecule level. Analytical and bioanalytical chemistry\| PubMed ID: 30824965	2019

Yi-Lun Ying

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