Person:
Rubio Retama, Benito Jorge

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First Name
Benito Jorge
Last Name
Rubio Retama
URI
https://hdl.handle.net/20.500.14352/77471
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Farmacia
Department
Química en Ciencias Farmacéuticas
Area
Química Física
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Item Type: Publication × Subject: 535.37 ×

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    Exploring the Origin of the Thermal Sensitivity of Near-Infrared-II Emitting Rare Earth Nanoparticles
    (Applied Materials and Interfaces, 2023) Hamraoui, Khouloud; Torres Vera, Vivian Andrea; Zabala Gutiérrez, Irene; Casillas Rubio, Alejandro; Alqudwa Fattouh, Mohammed; Benayas, Antonio; Marín, Riccardo; Natile, Marta María; Manso Silván, Miguel; Rubio Zuazo, Juan; Jaque, Daniel; Melle Hernández, Sonia; Gómez Calderón, Óscar; Rubio Retama, Benito Jorge
    Rare-earth doped nanoparticles (RENPs) are attracting increasing interest in materials science due to their optical, magnetic, and chemical properties. RENPs can emit and absorb radiation in the second biological window (NIR-II, 1000-1400 nm) making them ideal optical probes for photoluminescence (PL) in vivo imaging. Their narrow emission bands and long PL lifetimes enable autofluorescence-free multiplexed imaging. Furthermore, the strong temperature dependence of the PL properties of some of these RENPs makes remote thermal imaging possible. This is the case of neodymium and ytterbium co-doped NPs that have been used as thermal reporters for in vivo diagnosis of, for instance, inflammatory processes. However, the lack of knowledge about how the chemical composition and architecture of these NPs influence their thermal sensitivity impedes further optimization. To shed light on this, we have systematically studied their emission intensity, PL decay time curves, absolute PL quantum yield, and thermal sensitivity as a function of the core chemical composition and size, active-shell, and outer-inert-shell thicknesses. The results revealed the crucial contribution of each of these factors in optimizing the NP thermal sensitivity. An optimal active shell thickness of around 2 nm and an outer inert shell of 3.5 nm maximize the PL lifetime and the thermal response of the NPs due to the competition between the temperature-dependent back energy transfer, the surface quenching effects, and the confinement of active ions in a thin layer. These findings pave the way for a rational design of RENPs with optimal thermal sensitivity.
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    Ion-induced bias in Ag2S luminescent nanothermometers
    (Nanoscale, 2023) París Ogayar, Marina; Méndez González, Diego; Zabala Gutiérrez, Irene; Artiga , Alvaro; Rubio Retama, Benito Jorge; Gómez Calderón, Óscar; Melle Hernández, Sonia; Alda Serrano, Javier; Espinosa, Ana; Jaque, Daniel; Marín Viadel, Ricardo
    Luminescence nanothermometry allows measuring temperature remotely and in a minimally invasive way by using the luminescence signal provided by nanosized materials. This technology has allowed, for example, the determination of intracellular temperature and in vivo monitoring of thermal processes in animal models. However, in the biomedical context, this sensing technology is crippled by the presence of bias (cross-sensitivity) that reduces the reliability of the thermal readout. Bias occurs when the impact of environmental conditions different from temperature also modifies the luminescence of the nanothermometers. Several sources that cause loss of reliability have been identified, mostly related to spectral distortions due to interaction between photons and biological tissues. In this work, we unveil an unexpected source of bias induced by metal ions. Specifically, we demonstrate that the reliability of Ag2S nanothermometers is compromised during the monitoring of photothermal processes produced by iron oxide nanoparticles. The observed bias occurs due to the heat-induced release of iron ions, which interact with the surface of the Ag2S nanothermometers, enhancing their emission. The results herein reported raise a warning to the community working on luminescence nanothermometry, since they reveal that the possible sources of bias in complex biological environments, rich in molecules and ions, are more numerous than previously expected.