An official website of the United States government
Abstract MicroRNAs (miRNAs) play important roles in posttranscriptional gene regulation. Aberrations in the miRNA levels have been the cause behind various diseases, including periodontitis. Therefore, sensitive, specific, and accurate detection of disease‐associated miRNAs is vital to early diagnosis and can facilitate inhibitor screening and drug design. In this study, we developed a label‐free, real‐time sensing method for the detection of miR31, which has been frequently linked to periodontitis, using an engineered protein nanopore and in the presence of a complementary ssDNA as a molecular probe. Our method is rapid and highly sensitive with nanomolar concentration of miR31 that could be determined in minutes. Furthermore, our sensor showed high selectivity toward the target miR31 sequence even in the presence of interfering nucleic acids. In addition, artificial saliva and human saliva samples were successfully analyzed. Our developed nanopore sensing platform could be used to detect other miRNAs and offers a potential application for the clinical diagnosis of disease biomarkers.
more »
« less
Displacement chemistry-based nanopore analysis of nucleic acids in complicated matrices
To overcome the effect of other components of complicated biological samples on nanopore stochastic sensing, displacement chemical reaction was utilized to selectively extract the target nucleic acid from whole blood. Given its simplicity and high sensitivity for detecting nucleic acids, our developed displacement chemistry-based nanopore sensing strategy offers the potential for fieldable/point-of-care diagnostic applications.
more »
« less
- Award ID(s):
- 1708596
- PAR ID:
- 10094109
- Date Published:
- Journal Name:
- Chemical Communications
- Volume:
- 54
- Issue:
- 99
- ISSN:
- 1359-7345
- Page Range / eLocation ID:
- 13977 to 13980
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract Nanopores are increasingly powerful tools for single molecule sensing, in particular, for sequencing DNA, RNA and peptides. This success has spurred efforts to sequence non-canonical nucleic acid bases and amino acids. While canonical DNA and RNA bases have pKas far from neutral, certain non-canonical bases, natural RNA modifications, and amino acids are known to have pKas near neutral pHs at which nanopore sequencing is typically performed. Previous reports have suggested that the nanopore signal may be sensitive to the protonation state of an individual moiety. We sequenced ion currents with the MspA nanopore using a single stranded DNA containing a single non-canonical DNA base (Z) at various pH conditions. The Z-base has a near-neutral pKa ∼ 7.8. We find that the measured ion current is remarkably sensitive to the protonation state of the Z-base. We demonstrate how nanopores can be used to localize and determine the pKa of individual moieties along a polymer. More broadly, these experiments provide a path to mapping different protonation sites along polymers and give insight in how to optimize sequencing of polymers that contain moieties with near-neutral pKas.more » « less
-
Abstract In this review, recent research efforts that aimed at developing nanopore sensors for detection of metal ions, which play a crucial role in environmental safety and human health, are highlighted. Protein pores use three stochastic sensing‐based strategies for metal ion detection. The first strategy is to construct engineered nanopores with metal ion binding sites, so that the interaction between the target analytes and the nanopore can slow the movement of metal ions in the nanochannel. Second, large molecules such as nucleic acids and especially peptides can be utilized as external selective molecular probes to detect metal ions based on the conformational change of the ligand molecules induced by the metal ion–ligand chelation/coordination interaction. Third, enzymatic reactions can also be used as an alternative to the molecule probe strategy in the situation that a sensitive and selective probe molecule for the target analyte is difficult to obtain. On the other hand, by taking advantage of steady‐state analysis, synthetic nanopores mainly use two strategies (modification and modification‐free) to detect metals. Given the advantages of high sensitivity and selectivity, and label‐free detection, nanopore‐based metal ion sensors should find useful application in many fields, including environmental monitoring, medical diagnosis, and so on.more » « less
-
Pore-based structures occur widely in living organisms. Ion channels embedded in cell membranes, for example, provide pathways, where electron and proton transfer are coupled to the exchange of vital molecules. Learning from mother nature, a recent surge in activity has focused on artificial nanopore architectures to effect electrochemical transformations not accessible in larger structures. Here, we highlight these exciting advances. Starting with a brief overview of nanopore electrodes, including the early history and development of nanopore sensing based on nanopore-confined electrochemistry, we address the core concepts and special characteristics of nanopores in electron transfer. We describe nanopore-based electrochemical sensing and processing, discuss performance limits and challenges, and conclude with an outlook for nextgeneration nanopore electrode sensing platforms and the opportunities they present.more » « less
-
The application of solid-state (SS) nanopore devices to single-molecule nucleic acid sequencing has been challenging. Thus, the early successes in applying SS nanopore devices to the more difficult class of biopolymer, glycosaminoglycans (GAGs), have been surprising, motivating us to examine the potential use of an SS nanopore to analyze synthetic heparan sulfate GAG chains of controlled composition and sequence prepared through a promising, recently developed chemoenzymatic route. A minimal representation of the nanopore data, using only signal magnitude and duration, revealed, by eye and image recognition algorithms, clear differences between the signals generated by four synthetic GAGs. By subsequent machine learning, it was possible to determine disaccharide and even monosaccharide composition of these four synthetic GAGs using as few as 500 events, corresponding to a zeptomole of sample. These data suggest that ultrasensitive GAG analysis may be possible using SS nanopore detection and well-characterized molecular training sets.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/c8cc07944g
