Nanopore sensing involves an electrophoretic transport of analytes through a nanoscale pore, permitting label-free sensing at the single-molecule level. However, to date, the detection of individual small proteins has been challenging, primarily due to the poor signal/noise ratio that these molecules produce during passage through the pore. Here, we show that fine adjustment of the buffer pH, close to the isoelectric point, can be used to slow down the translocation speed of the analytes, hence permitting sensing and characterization of small globular proteins. Ubiquitin (Ub) is a small protein of 8.5 kDa, which is well conserved in all eukaryotes. Ub conjugates to proteins as a posttranslational modification called ubiquitination. The immense diversity of Ub substrates, as well as the complexity of Ub modification types and the numerous physiological consequences of these modifications, make Ub and Ub chains an interesting and challenging subject of study. The ability to detect Ub and to identify Ub linkage type at the single-molecule level may provide a novel tool for investigation in the Ub field. This is especially adequate because, for most ubiquitinated substrates, Ub modifies only a few molecules in the cell at a given time. Applying our method to the detection of mono- and poly-Ub molecules, we show that we can analyze their characteristics using nanopores. Of particular importance is that two Ub dimers that are equal in molecular weight but differ in 3D structure due to their different linkage types can be readily discriminated. Thus, to our knowledge, our method offers a novel approach for analyzing proteins in unprecedented detail using solid-state nanopores. Specifically, it provides the basis for development of single-molecule sensing of differently ubiquitinated substrates with different biological significance. Finally, our study serves as a proof of concept for approaching nanopore detection of sub-10-kDa proteins and demonstrates the ability of this method to differentiate among native and untethered proteins of the same mass.
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http://dx.doi.org/10.1016/j.bpj.2015.03.025 | DOI Listing |
ACS Appl Bio Mater
January 2025
Laboratório de Processos Eletroquímicos e Corrosão-ELETROCORR, Departamento de Metalurgia, Universidade Federal do Rio Grande do Sul, Avenida Bento Gonçalves 9500, 91501-970 Porto Alegre, Brazil.
This study presents an innovative approach to creating antibacterial aluminum surfaces by combining the antibacterial properties of silver nanoparticles (Ag NPs) with the nanoarchitecture of anodized aluminum oxide in one step. An Al-Ag alloy containing 10 wt % Ag was synthesized and anodized in 0.3 M oxalic acid.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Division of Micro and Nanosystems (MST), School of Electrical Engineering and Computer Science (EECS), KTH Royal Institute of Technology, Stockholm SE-10044, Sweden.
Controlled breakdown has emerged as an effective method for fabricating solid-state nanopores in thin suspended dielectric membranes for various biomolecular sensing applications. On an unpatterned membrane, the site of nanopore formation by controlled breakdown is random. Nanopore formation on a specific site on the membrane has previously been realized using local thinning of the membrane by lithographic processes or laser-assisted photothermal etching under immersion in an aqueous salt solution.
View Article and Find Full Text PDFChem Soc Rev
January 2025
Faculty of Chemistry and Food Chemistry, TU Dresden, Bergstrasse 66, 01062 Dresden, Germany.
Nanoporous solids offer a wide range of functionalities for industrial, environmental, and energy applications. However, only a limited number of porous materials are responsive, the nanopore dynamically alters its size and shape in response to external stimuli such as temperature, pressure, light or the presence of specific molecular stimuli adsorbed inside the voids deforming the framework. Adsorption-induced structural deformation of porous solids can result in unique counterintuitive phenomena.
View Article and Find Full Text PDFNanotechnology
January 2025
Department of Physics and Astronomy, Uppsala University, Box 516, Uppsala, Uppsala, SE-751 20, SWEDEN.
The growing world population and climate change are key drivers for the increasing pursuit of more efficient and environmentally-safe food production. In this scenario, the large scale use of herbicides demands the development new technologies to control and monitor the application of these compounds, due to their several environmental and health-related problems. Motivated by all these issues, in this work, a hybrid graphene/boron nitride nanopore is explore to detect/identify herbicide molecules (Glyphosate, AMPA, Diuron, and 2,4-D).
View Article and Find Full Text PDFNat Commun
January 2025
Key Laboratory of Precision and Intelligent Chemistry, Department of Applied Chemistry, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui, China.
Biological ion channels exhibit strong gating effects due to their zero-current closed states. However, the gating capabilities of artificial nanochannels have typically fallen short of biological channels, primarily owing to the larger nanopores that fail to completely block ion transport in the off-states. Here, we demonstrate solid-state hydrogen-bonded organic frameworks-based membranes to achieve high-performance ambient humidity-controlled proton gating, accomplished by switching the proton transport pathway instead of relying on conventional ion blockage/activation effects.
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