Person:
Zabala Gutiérrez, Irene

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First Name
Irene
Last Name
Zabala Gutiérrez
URI
https://hdl.handle.net/20.500.14352/86286
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Farmacia
Department
Química en Ciencias Farmacéuticas
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2022 - 20232
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Author: Gómez Calderón, Óscar × Subject: 620.3 ×

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    Boosting the Near-Infrared Emission of Ag2S Nanoparticles by a Controllable Surface Treatment for Bioimaging Applications
    (ACS Applied Materials & Interfaces, 2022) Zabala Gutiérrez, Irene; Gerke, Christoph; Shen, Yingli; Ximendes, Erving Clayton; Manso Silvan, Miguel; Marin, Riccardo; Jaque García, Daniel; Gómez Calderón, Óscar; Melle Hernández, Sonia; Rubio Retama, Benito Jorge
    Ag2S nanoparticles are the staple for high-resolution preclinical imaging and sensing owing to their photochemical stability, low toxicity, and photoluminescence (PL) in the second near-infrared biological window. Unfortunately, Ag2S nanoparticles exhibit a low PL efficiency attributed to their defective surface chemistry, which curbs their translation into the clinics. To address this shortcoming, we present a simple methodology that allows to improve the PL quantum yield from 2 to 10%, which is accompanied by a PL lifetime lengthening from 0.7 to 3.8 μs. Elemental mapping and X-ray photoelectron spectroscopy indicate that the PL enhancement is related to the partial removal of sulfur atoms from the nanoparticle’s surface, reducing surface traps responsible for nonradiative de-excitation processes. This interpretation is further backed by theoretical modeling. The acquired knowledge about the nanoparticles’ surface chemistry is used to optimize the procedure to transfer the nanoparticles into aqueous media, obtaining water-dispersible Ag2S nanoparticles that maintain excellent PL properties. Finally, we compare the performance of these nanoparticles with other near-infrared luminescent probes in a set of in vitro and in vivo experiments, which demonstrates not only their cytocompatibility but also their superb optical properties when they are used in vivo, affording higher resolution images.
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    A brighter era for silver chalcogenide semiconductor nanocrystals
    (Optical Materials, 2023) Ming, Liyan; Zabala Gutiérrez, Irene; Gómez Calderón, Óscar; Melle Hernández, Sonia; Ximendes , Erwing; Rubio Retama, Benito Jorge; Marín, Riccardo
    Silver chalcogenide semiconductor nanocrystals (Ag2E SNCs) have become a household name in the biomedical field, where they are used as contrast agents in bioimaging, photothermal therapy agents, and luminescent nanothermometers. The prominent position they have come to occupy in this field stems from a unique combination of features, above all near-infrared excitation and emission alongside low cytotoxicity. However, the first reports on Ag2E SNCs showed that a great limitation of these luminescent nanomaterials resided in their low photoluminescence quantum yield, which results in reduced brightness: a crippling feature in bioimaging and biosensing. In this article, we provide an overview of the strategies developed to overcome this hurdle. These strategies aim to remedy the presence of defects in the SNC core and/or surface, the presence of metallic silver, and off-stoichiometric composition. These features stem from the high mobility and redox potential of Ag+ ions, alongside the difficulty in controlling the nucleation and growth rate of Ag2E SNCs. The effectiveness of each approach is discussed. Lastly, a perspective on future research efforts to make Ag2E SNCs even brighter – and thus more effective in biomedical applications – is provided, with the hope of inspiring further investigation on these nanomaterials with a rich, complex set of physicochemical and spectroscopic properties.