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To characterise bioelectrocatalytic oxygen reduction at gold nanoparticles (AuNPs) modified with Trametes hirsuta laccase (ThLc) combined electrochemical and quartz crystal microbalance measurements have been used. The electrodes with different degrees of AuNP-monolayer coverage, θ, have been studied. In every case of θ close to theoretically possible 44 ThLc molecules adsorbed at 22nm diameter AuNP. The bioelectrocatalytic current was recalculated down to the current at a single AuNP. Unexpectedly, the current at a single AuNP was higher when θ was higher. The maximum current reached at a single AuNP was 31·10(-18)A which corresponds to the enzyme turnover (kcat) 13s(-1). This rate is lower than the homogeneous ThLc turnover (190s(-1)) suggesting partial denaturation of ThLc upon adsorption or that some ThLc are not in DET contact with the electrode surface.
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http://dx.doi.org/10.1016/j.bioelechem.2013.09.004 | DOI Listing |
Mikrochim Acta
September 2025
College of Food Science and Engineering, Northwest A&F University, 22 Xinong Road, Yangling, 712100, Shaanxi, China.
Salmonella typhimurium (S. typhimurium) A dual-mode colorimetric/photothermal immunochromatographic strip (ICS) employing hollow polydopamine nanoparticles (h-PDA) is reported for the ultrasensitive detection of Salmonella typhimurium (S. typhimurium).
View Article and Find Full Text PDFNanoscale
August 2025
Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand.
Detecting single point mutations, such as PIK3CA mutations, is vital for precision diagnostics but remains challenging due to subtle sequence differences. This study introduces a machine learning-assisted colorimetric biosensor that utilizes DNA-templated gold nanoparticle (AuNP) growth for sensitive and specific single point mutation detection. The biosensor employs a hairpin DNA probe that selectively hybridizes with mutant PIK3CA sequences.
View Article and Find Full Text PDFACS Appl Mater Interfaces
September 2025
Advanced Materials Laboratory of Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China.
Noble metal nanostructures are attractive substrates for surface-enhanced Raman scattering (SERS) but face persistent challenges in combining efficient hot-spot engineering with scalable fabrication. This paper presents a high-throughput, hot-spot-designable approach for assembling gold nanoparticles (AuNPs) onto micrometer-scale, two-dimensional polymer single-crystal templates, producing ∼10 uniform AuNP assemblies per milliliter. The assemblies, with planar micrometer-scale dimensions, are fully compatible with commercial confocal Raman systems.
View Article and Find Full Text PDFMethods
August 2025
Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea; Center for Advanced Reaction Dynamics (CARD), Institute for Basic Science (IBS), Daejeon 34141, Republic of Korea. Electronic address:
Measuring the conformational distribution of small proteins is essential to understanding their role in biological systems. Multi-Tilt Nanoparticle-aided cryo-electron microscopy sampling (MT-NACS) was devised to measure the three-dimensional interparticle distance distribution (P(d)) of two gold nanoparticles (AuNPs) labeled on a protein by taking cryogenic electron microscopy (cryo-EM) images at multiple-tilt angles. However, tracking the same particles in a pseudo-tomographic manner during the multi-tilt cryo-EM experiments and data analysis requires extensive time and effort.
View Article and Find Full Text PDFChem Sci
September 2025
CIC biomaGUNE, Basque Research and Technology Alliance (BRTA) 20014 Donostia-San Sebastián Spain
Motivated by potential applications in fields such as medicine or materials science, various methodologies have been developed for the preparation of so-called spherical nucleic acids, based on oligonucleotides and metal nanoparticles. Despite optimization through various parameters such as loading efficiency or nanoconjugate stability, much remains to be known regarding the actual conformations of oligonucleotides and their interactions with the nanoparticle surface. We employed a combination of spectroscopic techniques and liquid transmission electron microscopy to analyze the interactions and conformations adopted by polyAdenine (polyA) and polyThymine (polyT) chains in contact with gold nanoparticles (AuNPs).
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