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The binding of disulfides to gold nanoparticles was investigated using fluorescence spectroscopy and a perylene-monoimide dye coupled to a dissymmetric disulfide via a tetraethyleneglycolalkyl chain (PMImSS). Quantum chemical calculations using the polarizable continuum model (PCM) predict a strong quenching of perylene-monoimide fluorescence by gold nanoparticles as a result of efficient excitation energy transfer from the dye to the particle. Such quenching is indeed observed when unfunctionalised gold nanoparticles are added to a solution of PMImSS. The fluorimetric titration curves show behaviour indicative of the existence of an equilibrium between free and bound ligands (association constant 5 x 10(5) M(-1)), whereas the affinity of thiols and disulfide for gold surfaces is in general assumed to be much higher. Gold nanoparticles fully functionalised with PMImSS were synthesised and purified. Fluorescence correlation spectroscopy shows the appearance of free PMImSS ligands in dilute (approx. pM) suspensions of these PMImSS-functionalised nanoparticles over a period of several days.
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http://dx.doi.org/10.1039/c0pp00063a | DOI Listing |
J Agric Food Chem
September 2025
Guangdong Provincial Key Laboratory of Food Quality and Safety/Nation-Local Joint Engineering Research Center for Machining and Safety of Livestock and Poultry Products, South China Agricultural University, Guangzhou 510642, China.
Adulterated yohimbine (YHB) in food poses a risk to public health, making it imperative to develop fast and sensitive detection methods. In this study, computational-chemistry-based prediction was employed to design YHB haptens for generating the high-affinity monoclonal antibody Yohi-4A7, which exhibited an optimal half-inhibitory concentration (IC) of 1.69 ng/mL against YHB.
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September 2025
Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing 210023, P. R. China.
Electroactive bacteria (EAB) hold great promise for the development of electrochemical biosensors given their unique ability to transfer electrons extracellularly via specialized pathways, a process termed extracellular electron transfer (EET). Ongoing research aims to overcome current limitations and fully harness the potential of EABs for high-performance biosensing applications. Herein, we report the fabrication of an electrochemical microsensor based on biomineralized electroactive bacteria, specifically MR-1.
View Article and Find Full Text PDFIndian J Nucl Med
August 2025
Department of Physics, Shi.C., Islamic Azad University, Shiraz, Iran.
Background: Another approach to improve the dose conformity is to use charged particles like protons instead of the conventional X- and γ-rays. Protons exhibit a specific depth-dose distribution which allows to achieve a more targeted dose deposition and a significant sparing of healthy tissue behind the tumor. In particular, proton therapy has, therefore, become a routinely prescribed treatment for tumors located close to sensitive structures.
View Article and Find Full Text PDFDalton Trans
September 2025
Department of Chemistry, Istanbul Technical University, Maslak, Istanbul, 34469, Türkiye.
A novel phthalonitrile derivative (a) containing three functional groups (hexyl, aminated ester, phenoxy) was synthesized and subsequently cyclotetramerized in the presence of the corresponding metal chloride salts to obtain hexadeca-substituted metal {M = Cu(II) and Co(II)} phthalocyanines (b and c). The water-soluble phthalocyanines (d and e) were prepared by treating the newly synthesized complexes (b and c) with methyl iodide. Moreover, gold nanoparticles (1) and silver nanoparticles (2) were prepared, and their surfaces were modified with quaternary phthalocyanines (d and e).
View Article and Find Full Text PDFAnal Chem
September 2025
Institute of Digitized Medicine and Intelligent Technology, Wenzhou Medical University, Wenzhou 325000, P. R. China.
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