A central topic in single-atom catalysis is building strong interactions between single atoms and the support for stabilization. Herein we report the preparation of stabilized single-atom catalysts via a simultaneous self-reduction stabilization process at room temperature using ultrathin two-dimensional Ti3–x C2T y MXene nanosheets characterized by abundant Ti-deficit vacancy defects and a high reducing capability. The single atoms therein form strong metal–carbon bonds with the Ti3–x C2T y support and are therefore stabilized onto the sites previously occupied by Ti. Pt-based single-atom catalyst (SAC) Pt1/Ti3–x C2T y offers a green route to utilizing greenhouse gas CO2, via the formylation of amines, as a C1 source in organic synthesis. DFT calculations reveal that, compared to Pt nanoparticles, the single Pt atoms on Ti3–x C2T y support feature partial positive charges and atomic dispersion, which helps to significantly decrease the adsorption energy and activation energy of silane, CO2, and aniline, thereby boosting catalytic performance. We believe that these results would open up new opportunities for the fabrication of SACs and the applications of MXenes in organic synthesis.

Hybrid nanostructures containing neodymium-doped nanoparticles and infrared-emitting quantum dots constitute highly sensitive luminescent thermometers operating in the second biological window. They demonstrate that accurate subtissue fluorescence thermal sensing is possible.

Esta es la versión de autor del artículo publicado en: This is an author produced version of a paper published in: possible to achieve full control over the intratumoral temperature increment during PTT. The differences observed between intratumoral and surface temperatures in this comprehensive investigation, through different irradiation conditions, highlight the need for real-time control of the intratumoral temperature that allows for a dynamic adjustment of the treatment conditions in order to maximize the efficacy of the therapy.3

Over the past decade, near-infrared (NIR)-emitting nanoparticles have increasingly been investigated in biomedical research for use as fl uorescent imaging probes. Here, high-quality water-dispersible core/shell/shell PbS/ CdS/ZnS quantum dots (hereafter QDs) as NIR imaging probes fabricated through a rapid, cost-effective microwave-assisted cation exchange procedure are reported. These QDs have proven to be water dispersible, stable, and are expected to be nontoxic, resulting from the growth of an outer ZnS shell and the simultaneous surface functionalization with mercaptopropionic acid ligands. Care is taken to design the emission wavelength of the QDs probe lying within the second biological window (1000-1350 nm), which leads to higher penetration depths because of the low extinction coeffi cient of biological tissues in this spectral range. Furthermore, their intense fl uorescence emission enables to follow the real-time evolution of QD biodistribution among different organs of living mice, after low-dose intravenous administration. In this paper, QD platform has proven to be capable (ex vivo and in vitro) of high-resolution thermal sensing in the physiological temperature range. The investigation, together with the lack of noticeable toxicity from these PbS/CdS/ZnS QDs after preliminary studies, paves the way for their use as outstanding multifunctional probes both for in vitro and in vivo applications in biomedicine.

Light scattering by biological tissues sets a limit to the penetration depth of high-resolution optical microscopy imaging of live mammals in vivo. An effective approach to reduce light scattering and increase imaging depth is by extending the excitation and emission wavelengths to the > 1000 nm second near-infrared (NIR-II), also called the short-wavelength infrared (SWIR) window. Here, we show biocompatible core-shell lead sulfide/cadmium sulfide (PbS/CdS) quantum dots emitting at ~1880 nm and superconducting nanowire single photon detectors (SNSPD) for single-photon detection up to 2000 nm, enabling one-photon excitation fluorescence imaging window in the 1700–2000 nm (NIR-IIc) range with 1650 nm excitation, the longest one-photon excitation and emission for in vivo mouse imaging to date. Confocal fluorescence imaging in NIR-IIc reached an imaging depth of ~ 1100 μm through intact mouse head, and enabled non-invasive cellular-resolution imaging in the inguinal lymph nodes (LNs) of mice without any surgery. We achieve In vivo molecular imaging of high endothelial venules (HEVs) with diameter down to ~ 6.6 μm and CD169+ macrophages and CD3+ T cells in the lymph nodes, opening the possibility of non-invasive intravital imaging of immune trafficking in lymph nodes at the single-cell/vessel level longitudinally.