Nanopore protein (α-hemolysin) was used to detect sub-nanosized plastic particles leached from a PE-coated paper cup. These sub-nanosized plastic particles can increase the inflammation response of ...macrophages.
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•Nanopore sensing detects sub-nanosized plastics in PE-coated paper cups.•Sub-nanosized plastic particles in paper cups were 1.8 times more detected in boiled water than in room temperature water.•Sub-nanosized and microplastic particles alter cell membrane dynamics.•Sub-nanosized plastic particles can induce inflammatory cell responses.
In recent years, there has been growing global concern about environmental pollution, and the increasing use of plastic products has made microplastics a serious environmental pollutant worldwide. Accordingly, the development of microplastic detection methods and research on the harmful effects of microplastics on human health are being actively pursued. In this study, we detected particle leaching from PE-coated paper cups using label-free nanopore sensing to identify and quantify the presence of sub-nanosized plastic particles. Plastic particles leached from the paper cups were classified as < 1 nm and > 1 nm, and their interactions with artificial cell membranes and inflammatory responses in the cells were evaluated. The results demonstrated that in a commonly used paper cup, particles < 1.4 nm were present at a concentration of approximately 1.13 mM in hot water and 0.62 mM in room-temperature water. It was demonstrated that plastic particles < 1 nm could condense the artificial cell membrane, whereas particles > 1 nm could thicken the artificial cell membrane. Furthermore, both size ranges of particles leached from the paper cups triggered an inflammatory response in the cells, with the inflammatory response increasing in proportion to the concentration and treatment time. The detection and analysis revealed the presence of sub-nanosized plastic particles in PE-coated paper cups, which are commonly used in daily life. These particles pose health threats and contribute to environmental pollution.
Nanoscale electrophoresis allows for unique separations of single molecules, such as DNA/RNA nucleobases, and thus has the potential to be used as single molecular sensors for exonuclease sequencing. ...For this to be envisioned, label‐free detection of the nucleotides to determine their electrophoretic mobility (i.e., time‐of‐flight, TOF) for highly accurate identification must be realized. Here, for the first time a novel nanosensor is shown that allows discriminating four 2‐deoxyribonucleoside 5'‐monophosphates, dNMPs, molecules in a label‐free manner by nanoscale electrophoresis. This is made possible by positioning two sub‐10 nm in‐plane pores at both ends of a nanochannel column used for nanoscale electrophoresis and measuring the longitudinal transient current during translocation of the molecules. The dual nanopore TOF sensor with 0.5, 1, and 5 µm long nanochannel column lengths discriminates different dNMPs with a mean accuracy of 55, 66, and 94%, respectively. This nanosensor format can broadly be applicable to label‐free detection and discrimination of other single molecules, vesicles, and particles by changing the dimensions of the nanochannel column and in‐plane nanopores and integrating different pre‐ and postprocessing units to the nanosensor. This is simple to accomplish because the nanosensor is contained within a fluidic network made in plastic via replication.
A dual‐nanopore time‐of‐flight (TOF) sensor, which consists of two in‐plane nanopores formed at both ends of a nanochannel column, is designed and fabricated to determine the mobility of single molecules in nanoscale electrophoresis in a label‐free manner. This novel nanosensor with a 5 µm long nanochannel column demonstrates discrimination of four deoxynucleotide monophosphates (dNMPs) molecules with a mean identification accuracy of 94%.
Nanopore techniques offer a low-cost, label-free, and high-throughput platform that could be used in single-molecule biosensing and in particular DNA sequencing. Since 2010, graphene and other ...two-dimensional (2D) materials have attracted considerable attention as membranes for producing nanopore devices, owing to their subnanometer thickness that can in theory provide the highest possible spatial resolution of detection. Moreover, 2D materials can be electrically conductive, which potentially enables alternative measurement schemes relying on the transverse current across the membrane material itself and thereby extends the technical capability of traditional ionic current-based nanopore devices. In this review, we discuss key advances in experimental and computational research into DNA sensing with nanopores built from 2D materials, focusing on both the ionic current and transverse current measurement schemes. Challenges associated with the development of 2D material nanopores toward DNA sequencing are further analyzed, concentrating on lowering the noise levels, slowing down DNA translocation, and inhibiting DNA fluctuations inside the pores. Finally, we overview future directions of research that may expedite the emergence of proof-of-concept DNA sequencing with 2D material nanopores.
In article number 1804078, Hai‐Chen Wu and co‐workers develop a strategy for the ultrasensitive detection of cancer biomarkers based on the combination of a sandwich assay, “click” chemistry, and ...DNA‐assisted nanopore sensing. The limit of detection of the strategy can be as low as the femtomolar level. Furthermore, it can effectively eliminate interferences from plasma proteins and be applied in the clinical detection of cancer biomarkers.
Enzymatic cascade reactions are widely used to synthesize complex molecules from simple precursors. The major underlying mechanism of cascade reactions is substrate channelling, where intermediates ...of different enzymatic steps are not in equilibrium with the bulk solution. Here, we report a nanopore sensing assay that allows accurate quantification of all the reaction intermediates and the product of an artificial three‐enzyme system. A DNA–peptide complex is used as the initial substrate which undergoes sequential enzymatic cleavages in solution. All the temporal changes of the intermediates and product can be obtained through nanopore translocation recordings. Furthermore, we find that in a confined environment such as liposome, substrate channelling occurs between two sets of the three enzymes. Our results demonstrate a novel and powerful approach to determine and quantify substrate channelling effects, which is potentially useful for designing and evaluating multienzyme systems.
A nanopore sensing assay is developed to resolve cascade reactions of an artificial three‐enzyme system. In a confined environment such as liposomes, substrate‐channelling effects are observed between two sets of the three enzymes.
Both human telomere and proto-oncogene c-MYC can form G-quadruplex (G4) with various conformations. Porphyrin derivative (TMPyP4) could stabilize G4, and thus is considered as a potential drug for ...anticancer therapeutics. In this paper, the translocation behaviors of three typical G4s (telomere basket, telomere hybrid-1 and c-MYC Pu22 parallel) and their interaction with TMPyP4 were investigated with a single protein nanopore sensing interface with the same main electrolyte of 0.5 M tetramethylammonium chloride. As observed by the statistics of the dwell time of the current pulses, in the presence of K+, the parallel G4 is more stable than the hybrid-1 G4, while the basket G4 in the presence of Na+ exhibited shortest duration. The dwell time of all of the G4s increased as the result of interaction with TMPyP4, indicating an obvious stabilizing effect. This study demonstrated that the single nanopore sensing interface not only reveal the stability of various G4 conformations at a single-molecule level, but also provide the interaction information of a ligand, which could be useful in the drug design.
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•The translocation behaviors of three G4s G4 were examined, and compared for the first time with nanopore sensing interface.•Interaction of porphyrin derivative TMPyP4 with G4s was investigated and compared with the proposed method.•This work provides a new method for obtaining knowledge about the stability of G4 itself and its interaction with ligand.
Protein biomarkers in blood have been widely used in the early diagnosis of disease. However, simultaneous detection of many biomarkers in a single sample remains challenging. Herein, we show that ...the combination of a sandwich assay and DNA‐assisted nanopore sensing could unambiguously identify and quantify several antigens in a mixture. We use five barcode DNAs to label different gold nanoparticles that can selectively bind specific antigens. After the completion of the sandwich assay, barcode DNAs are released and subject to nanopore translocation tests. The distinct current signatures generated by each barcode DNA allow simultaneous quantification of biomarkers at picomolar level in clinical samples. This approach would be very useful for accurate and multiplexed quantification of cancer‐associated biomarkers within a very small sample volume, which is critical for non‐invasive early diagnosis of cancer.
Multiplexing with nanopores: A new strategy for sensing multiple cancer biomarkers in a single sample through the combination of a sandwich assay and barcode DNA‐assisted nanopore sensing is reported. The characteristic events produced by each barcode DNA can be used to detect the presence of its corresponding biomarker and quantify its concentration. This strategy could lead to rapid and specific cancer diagnosis in a single drop of blood.
In this review, we describe the importance and possible electrochemical screening methods for the illicit drug – cocaine. It covers the detection at bare and modified solid electrodes, soft ...electrified junctions and nanopore sensing. Emphasis is given on interfacial modification techniques and electroanalytical parameters for cocaine detection in different environments, covering the detection from both, model and real samples.
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•Electrochemistry can be used for selective cocaine sensing from real samples.•Selective detection of cocaine can be achieved with pristine carbon based electrodes.•Development of cocaine specific aptamer brought major development to the filed.•Soft and polarizable interphases are emerging sensing platforms for cocaine detection.•Little focus is given to electrochemically detect cocaine metabolites.
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