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All-inorganic colloidal cesium lead halide perovskite quantum dots (CsPbX₃, X = Cl, Br, I) are revealed to be a new class of favorable optical-gain materials, which show ­combined merits of both colloidal quantum dots and halide perovskites. Low-threshold and ­ultrastable stimulated emission is ­demonstrated under atmospheric conditions with wavelength tunability across the whole ­visible spectrum via either size or composition control.

Over the past decade, near-infrared (NIR)-emitting nanoparticles have increasingly been investigated in biomedical research for use as fluorescent 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 coefficient of biological tissues in this spectral range. Furthermore, their intense fluorescence 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.

Low-dose in vivo near-infrared (NIR) fluorescence imaging is achieved by using carefully designed PbS/CdS/ZnS quantum dots (QDs), intensely emitting within the second biological window (1000–1350 nm). Moreover, preliminary studies both in vitro and in vivo have proven the lack of noticeable toxicity of these QDs. As an additional advantage, this NIR-fluorescence imaging platform has demonstrated useful multifunctionality, thus being capable, both ex vivo and in vitro, of high-resolution thermal sensing in the physiological temperature range.

A multifunctional nanoseaurchin probe in which mesoporous silica nanobeads with iron oxide nanoparticles embedded and multi-gold nanorods crystal-seeded are fabricated and labeled with umbilical cord mesenchymal stem cells through endocytosis. This nanoplatform enables efficient magnetic remote-controlled guiding for stem cell homing, and provides dual modalities of photoacoustic imaging and magnetic resonance imaging for in situ tracking and long-term monitoring to achieve therapeutic efficacy.

A therapeutic carrier in the second near-infrared (NIR) window is created that features magnetic target, magnetic resonance imaging (MRI) diagnosis, and photothermal therapy functions through the manipulation of a magnet and NIR laser. A covellite-based CuS in the form of rattle-type Fe₃O₄@CuS nanoparticles is developed to conduct photoinduced hyperthermia at 808 and 1064 nm of the first and second NIR windows, respectively. The Fe₃O₄@CuS nanoparticles exhibit broad NIR absorption from 700 to 1300 nm. The in vitro photothermal results show that the laser intensity obtained using 808 nm irradiation required a twofold increase in its magnitude to achieve the same damage in cells as that obtained using 1064 nm irradiation. Because of the favorable magnetic property of Fe₃O₄, magnetically guided photothermal tumor ablation is performed for assessing both laser exposures. According to the results under the fixed laser intensity and irradiation spot, exposure to 1064 nm completely removed tumors showing no signs of relapse. On the other hand, 808 nm irradiation leads to effective inhibition of growth that remained nearly unchanged for up to 30 d, but the tumors are not completely eliminated. In addition, MRI is performed to monitor rattle-type Fe₃O₄@CuS localization in the tumor following magnetic attraction.

An effective, near-infrared (NIR)-responsive rattle-type Fe₃O₄@CuS nanoparticle is developed to conduct magnetically guided photothermal tumor ablation and magnetic resonance imaging diagnosis through magnetic targeting. Based on the broad NIR absorption from 700 to 1300 nm, photothermal tumor ablation is evaluated by radiation at 808 and 1064 nm of the first and second NIR windows, respectively.

Silicon micropyramids with n⁺pp⁺ junctions are demonstrated to be efficient absorbers for integrated solar-driven hydrogen production systems enabling significant improvements in both photocurrent and onset potential. When conformally coated with MoS_xCl_y, a catalyst that has excellent catalytic activity and high optical transparency, the highest photocurrent density for Si-based photocathodes with earth-abundant catalysts is achieved.