Label-free and real-time single-molecule detection may aid the development of high-throughput biosensing platforms. Molecular fluctuations are a source of noise that often hinders single-molecule identification by obscuring the fine details of molecular identity. In this study, we report molecular identification through direct observation of quantum-fluctuation-induced inelastic noise in single organic molecules. We investigated current fluctuations flowing through a single molecule that is chemically connected to two electrodes. We found increased current oscillations synchronous to electric field excitations of characteristic molecular vibrational modes that contribute to inelastic electron tunnelling. This finding demonstrates a large contribution of charge interaction with nuclear dynamics on noise properties of single-molecule bridges and suggests a potential use of inelastic noise as a valuable molecular signature for single-molecule identification.
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http://dx.doi.org/10.1038/ncomms1141 | DOI Listing |
Elife
January 2025
Eikon Therapeutics Inc, Hayward, United States.
The regulation of cell physiology depends largely upon interactions of functionally distinct proteins and cellular components. These interactions may be transient or long-lived, but often affect protein motion. Measurement of protein dynamics within a cellular environment, particularly while perturbing protein function with small molecules, may enable dissection of key interactions and facilitate drug discovery; however, current approaches are limited by throughput with respect to data acquisition and analysis.
View Article and Find Full Text PDFRSC Adv
January 2025
Phenikaa University Nano Institute (PHENA), Phenikaa University Hanoi 12116 Vietnam
Surface-enhanced Raman spectroscopy (SERS) is widely recognized as a powerful analytical technique, offering molecular identification by amplifying characteristic vibrational signals, even at the single-molecule level. While SERS has been successfully applied for a wide range of targets including pesticides, dyes, bacteria, and pharmaceuticals, it has struggled with the detection of molecules with inherently low Raman scattering cross-sections. Urea, a key nitrogen-containing biomolecule and the diamide of carbonic acid, is a prime example of such a challenging target.
View Article and Find Full Text PDFCurr Opin Nephrol Hypertens
January 2025
Control of the immune response B and lymphoproliferation, CNRS UMR 7276, INSERM UMR 1262, University of Limoges, Centre de référence de l'amylose AL et autres maladies par dépôts d'immunoglobuline monoclonale, Limoges, France; Service de néphrologie et Centre National de référence amylose AL et autres maladies à dépôts d'immunoglobulines monoclonales, Centre Hospitalier Universitaire, Université de Poitiers, Poitiers, France.
J Am Chem Soc
January 2025
Molecular Sensing and Imaging Center, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, P. R. China.
Nanopore technology holds great potential for single-molecule identification. However, extracting meaningful features from ionic current signals and understanding the molecular mechanisms underlying the specific features remain unresolved. In this study, we uncovered a distinctive ionic current pattern in a K238Q aerolysin nanopore, characterized by transient spikes superimposed on two stable transition states.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China.
Nanopores are promising sensors for glycan analysis with the accurate identification of complex glycans laying the foundation for nanopore-based sequencing. However, their applicability toward continuous glycan sequencing has not yet been demonstrated. Here, we present a proof-of-concept of glycan sequencing by combining nanopore technology with glycosidase-hydrolyzing reactions.
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