The cover illustrates the article "Ratiometric Nanothermometer Based on a Radical Excimer for In Vivo Sensing", involving a collaborative effort between ICMAB, CIBER-BBN, IBEC, ICREA and IPER-Hospital Sant Joan de Déu, and it is co-authored by Davide Blasi (ICMAB-CSIC), Nerea Gonzalez-Pato (ICMAB-CSIC), Xavier Rodriguez Rodriguez (ICMAB-CSIC), Iñigo Diez-Zabala (ICMAB-CSIC), Sumithra Yasaswini Srinivasan (ICMAB-CSIC), Núria Camarero (IBEC), Oriol Esquivias (ICMAB-CSIC), Mònica Roldán (IPER), Judith Guasch (ICMAB-CSIC, CIBER-BBN, Max Planck Partner Group), Anna Laromaine (ICMAB-CSIC), Pau Gorostiza (CIBER-BBN, IBEC, ICREA), Jaume Veciana (ICMAB-CSIC, CIBER-BBN), and Imma Ratera (ICMAB-CSIC, CIBER-BBN).
The cover illustration depicts organic nanoparticles based on persistent TTM radicals containing excimers and isolated molecules. These nanoparticles exhibit all characteristics of ratiometric nanothermometers, showing excellent temperature sensitivity, reversibility, and high colloidal stability. In-vivo experiments made with Caenorhabditis elegans (C. elegans) indicate that they can monitor temperature changes at the (nano)-micron scale from 5 to 40 °C, with very high sensitivity indicating the considerable potential applications in the biological thermometry field.
Ratiometric fluorescent nanothermometers with near-infrared emission play an important role in in vivo sensing since they can be used as intracellular thermal sensing probes with high spatial resolution and high sensitivity, to investigate cellular functions of interest in diagnosis and therapy, where current approaches are not effective. Herein, the temperature-dependent fluorescence of organic nanoparticles is designed, synthesized, and studied based on the dual emission, generated by monomer and excimer species, of the tris(2,4,6-trichlorophenyl)methyl radical (TTM) doping organic nanoparticles (TTMd-ONPs), made of optically neutral tris(2,4,6-trichlorophenyl)methane (TTM-αH), acting as a matrix.
The excimer emission intensity of TTMd-ONPs decreases with increasing temperatures whereas the monomer emission is almost independent and can be used as an internal reference. TTMd-ONPs show a great temperature sensitivity (3.4% K−1 at 328 K) and a wide temperature response at ambient conditions with excellent reversibility and high colloidal stability. In addition, TTMd-ONPs are not cytotoxic and their ratiometric outputs are unaffected by changes in the environment. Individual TTMd-ONPs are able to sense temperature changes at the nano-microscale. In vivo thermometry experiments in Caenorhabditis elegans (C. elegans) worms show that TTMd-ONPs can locally monitor internal body temperature changes with spatio-temporal resolution and high sensitivity, offering multiple applications in the biological nanothermometry field.
Ratiometric Nanothermometer Based on a Radical Excimer for In Vivo Sensing
Davide Blasi, Nerea Gonzalez-Pato, Xavier Rodriguez Rodriguez, Iñigo Diez-Zabala, Sumithra Yasaswini Srinivasan, Núria Camarero, Oriol Esquivias, Mònica Roldán, Judith Guasch, Anna Laromaine, Pau Gorostiza, Jaume Veciana, Imma Ratera