Real-time intracellular temperature imaging using lanthanide-bearing polymeric micelles

Measurement of thermogenesis in individual cells is a remarkable challenge due to the complexity of the biochemical environment (such as pH and ionic strength) and to the rapid and yet not well-understood heat transfer mechanisms throughout the cell. Here, we present a unique system for intracellular temperature mapping in a fluorescence microscope (uncertainty of 0.2 K) using rationally designed luminescent Ln3+-bearing polymeric micellar probes (Ln = Sm, Eu) incubated in breast cancer MDA-MB468 cells. Two-dimensional (2D) thermal images recorded increasing the temperature of the cells culture medium between 296 and 304 K shows inhomogeneous intracellular temperature progressions up to ∼20 degrees and subcellular gradients of ∼5 degrees between the nucleolus and the rest of the cell, illustrating the thermogenic activity of the different organelles and highlighting the potential of this tool to study intracellular processes.publishe

Luminescent temperature probes for real-time intracellular thermometry and magnetic hypertermia

Resumen del trabajo presentado a la XXXVIII Reunión Bienal de la Real Sociedad Española de Química, celebrada en el Palacio de Congresos de Granada, del 27 de junio al 30 de junio de 2022.This work was supported by the Spanish Ministry of Science Innovation and Universities [Grant No: PGC2018_095795_B_I00] and Diputación General de Aragón [E11/17R]. The support of the European Union's Horizon 2020 FET Open program under grant agreements No. 801305 (NanoTBTech) and 829162 (Hotzymes) is also acknowledged.Peer reviewe

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[Ga3+8Sm3+2, Ga3+8Tb3+2] Metallacrowns are Highly Promising Ratiometric Luminescent Molecular Nanothermometers Operating at Physiologically Relevant Temperatures

Nanothermometry is the study of temperature at the submicron scale with a broad range of potential applications, such as cellular studies or electronics. Molecular luminescent- based nanothermometers offer a non- contact means to record these temperatures with high spatial resolution and thermal sensitivity. A luminescent- based molecular thermometer comprised of visible- emitting Ga3+/Tb3+ and Ga3+/Sm3+ metallacrowns (MCs) achieved remarkable relative thermal sensitivity associated with very low temperature uncertainty of Sr=1.9- %- K- 1 and δT<0.045- K, respectively, at 328- K, as an aqueous suspension of polystyrene nanobeads loaded with the corresponding MCs. To date, they are the ratiometric molecular nanothermometers offering the highest level of sensitivity in the physiologically relevant temperature range.Metallacrown- based thermometry: Mixtures of luminescent Ga3+/Tb3+ and Ga3+/Sm3+ metallacrowns proved to be highly sensitive luminescent molecular thermometers. These were placed in polystyrene nanobeads for aqueous stabilization and demonstrate the promise of a molecular approach to nanothermometry.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/163582/3/chem202003239.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/163582/2/chem202003239-sup-0001-misc_information.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/163582/1/chem202003239_am.pd

Local Temperature Increments and Induced Cell Death in Intracellular Magnetic Hyperthermia

The generation of temperature gradients on nanoparticles heated externally by a magnetic field is crucially important in magnetic hyperthermia therapy. But the intrinsic low heating power of magnetic nanoparticles, at the conditions allowed for human use, is a limitation that restricts the general implementation of the technique. A promising alternative is local intracellular hyperthermia, whereby cell death (by apoptosis, necroptosis, or other mechanisms) is attained by small amounts of heat generated at thermosensitive intracellular sites. However, the few experiments conducted on the temperature determination of magnetic nanoparticles have found temperature increments that are much higher than the theoretical predictions, thus supporting the local hyperthermia hypothesis. Reliable intracellular temperature measurements are needed to get an accurate picture and resolve the discrepancy. In this paper, we report the real-time variation of the local temperature on γ-Fe2O3 magnetic nanoheaters using a Sm3+/Eu3+ ratiometric luminescent thermometer located on its surface during exposure to an external alternating magnetic field. We measure maximum temperature increments of 8 °C on the surface of the nanoheaters without any appreciable temperature increase on the cell membrane. Even with magnetic fields whose frequency and intensity are still well within health safety limits, these local temperature increments are sufficient to produce a small but noticeable cell death, which is enhanced considerably as the magnetic field intensity is increased to the maximum level tolerated for human use, consequently demonstrating the feasibility of local hyperthermia