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Surface-enhanced Raman scattering (SERS)-based sensing is promising in that it has potential to allow for highly sensitive, selective, and multiplexed detection and imaging. However, the controlled assembly and gap formation between plasmonic particles for generating strong SERS signals in a quantitative manner is highly challenging, especially on biodetection platforms, and particle-to-particle variation in the signal enhancement can vary by several orders of magnitude in a single batch, largely limiting the reliable use of SERS for practical sensing applications. Here, a hierarchic-nanocube-assembly based SERS (H-Cube-SERS) bioassay to controllably amplify the electromagnetic field between gold nanocubes (AuNCs) is developed. Based on this strategy, H-Cube-SERS assay allows for detecting target DNA with a wide dynamic range from 100 aM to 10 pM concentrations in a stable and reproducible manner. It is also found that the uniformly formed AuNCs with flat surfaces are much more suitable for highly sensitive, reliable, and quantitative biodetection assays due to faster DNA binding kinetics, sharper DNA melting transition, wider hot spot regions, and less dependence on light polarization direction than spherical Au nanoparticles with curved interfaces. This work paves the pathways to the quantitative and sensitive biodetection on a SERS platform and can be extended to other particle assembly systems.
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http://dx.doi.org/10.1021/acs.analchem.9b01272 | DOI Listing |
Spectrochim Acta A Mol Biomol Spectrosc
September 2025
College of Chemistry, Chemical Engineering and Material Science, Soochow University, No. 199 Ren'Ai Road, Suzhou 215123, China; Jiangsu Key Laboratory of Medical Optics, Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Science, Suzhou 215163, China. Electronic address: g
The dynamic monitoring of cell death processes remains a significant challenge due to the scarcity of highly sensitive molecular tools. In this study, two hemicyanine-based probes (5a-5b) with D-π-A structures were developed for organelle-specific viscosity monitoring. Both probes exhibited correlation with the Förster-Hoffmann viscosity-dependent relationship (R > 0.
View Article and Find Full Text PDFAnal Chem
September 2025
Department of Chemistry, The University of Akron, Akron, Ohio 44325, United States.
Tires are complex polymeric materials composed of rubber elastomers (both natural and synthetic), fillers, steel wire, textiles, and a range of antioxidant and curing systems. These constituents are distributed differently among the various tire parts, which are classified based on their function and proximity to the rim. This study presents a rapid and sensitive approach for the characterization of tire components using mild thermal desorption/pyrolysis (TDPy) coupled to direct analysis in real-time mass spectrometry (DART-MS).
View Article and Find Full Text PDFAnal Chem
September 2025
Jiaxing Key Laboratory of Molecular Recognition and Sensing, College of Biological and Chemical Engineering, Jiaxing University, Jiaxing 314001, China.
Despite the promise of electrochemical biosensors in amplified nucleic acid diagnostics, existing high-sensitivity platforms often rely on a multilayer surface assembly and cascade amplification confined to the electrode interface. These stepwise strategies suffer from inefficient enzyme activity, poor mass transport, and inconsistent probe orientation, which compromise the amplification efficiency, reproducibility, and practical applicability. To address these limitations, we report a programmable dual-phase electrochemical biosensing system that decouples amplification from signal transduction.
View Article and Find Full Text PDFJ Am Soc Mass Spectrom
September 2025
Chemistry Department, Indiana University, 800 E Kirkwood Ave, Bloomington, Indiana 47405.
In charge detection mass spectrometry (CD-MS) ions are trapped in an electrostatic linear ion trap (ELIT) where they oscillate back and forth through a conducting cylinder. The oscillating ions induce a periodic charge separation that is detected by a charge sensitive amplifier (CSA) connected to the cylinder. The resulting time domain signal is analyzed using short-time Fourier transforms to give the mass-to-charge ratio and charge for each ion, which are then multiplied to give the mass.
View Article and Find Full Text PDFRetina
September 2025
Department of Ophthalmology, Inselspital, Bern University Hospital, University of Bern, Freiburgstrasse 15, CH-3010.
Purpose: To evaluate inter-grader variability in posterior vitreous detachment (PVD) classification in patients with epiretinal membrane (ERM) and macular hole (MH) on spectral-domain optical coherence tomography (SD-OCT) and identify challenges in defining a reliable ground truth for artificial intelligence (AI)-based tools.
Methods: A total of 437 horizontal SD-OCT B-scans were retrospectively selected and independently annotated by six experienced ophthalmologists adopting four categories: 'full PVD', 'partial PVD', 'no PVD', and 'ungradable'. Inter-grader agreement was assessed using pairwise Cohen's kappa scores.