Correction: Perspectives for Ag2S NIR-II nanoparticles in biomedicine: from imaging to multifunctionality.

Correction for 'Perspectives for Ag2S NIR-II nanoparticles in biomedicine: from imaging to multifunctionality' by Yingli Shen, et al., Nanoscale, 2019, DOI: 10.1039/c9nr05733a.

Dynamic single gold nanoparticle visualization by clinical intracoronary optical coherence tomography.

The potential use of Gold Nanoparticles (GNPs) as contrast agents for clinical intracoronary frequency domain Optical Coherence Tomography (OCT) is here explored. The OCT contrast enhancement caused by GNPs of different sizes and morphologies has been systematically investigated and correlated with their optical properties. Among the different GNPs commercially available with plasmon resonances close to the operating wavelength of intracoronary OCT (1.3 µm), Gold Nanoshells (GNSs) have provided the best OCT contrast due to their largest scattering cross section at this wavelength. Clinical intracoronary OCT catheters are here demonstrated to be capable of three dimensional visualization and real-time tracking of individual GNSs. Results here included open an avenue to novel application of intravascular clinical OCT in combination with GNPs, such as real time evaluation of intravascular obstructions or pressure gradients.

Overcoming Autofluorescence: Long-Lifetime Infrared Nanoparticles for Time-Gated In Vivo Imaging.

The always present and undesired contribution of autofluorescence is here completely avoided by combining a simple time gating technology with long lifetime neodymium doped infrared-emitting nanoparticles.

Subtissue Imaging and Thermal Monitoring of Gold Nanorods through Joined Encapsulation with Nd-Doped Infrared-Emitting Nanoparticles.

Encapsulation of gold nanorods together with Nd-doped fluorescent nanoparticles in a biocompatible polymer creates multifunctional nanostructures, whose infrared fluorescence allows their subcutaneous localization in biological tissues while also adding the ability to measure the temperature from the emitted light in order to better monitor the light-to-heat conversion of the gold nanorods during photothermal therapy.

Correction: Self-monitored photothermal nanoparticles based on core-shell engineering.

Correction for 'Self-monitored photothermal nanoparticles based on core-shell engineering' by Erving C. Ximendes et al., Nanoscale, 2016, 8, 3057-3066.

Hybrid nanostructures for high-sensitivity luminescence nanothermometry in the second biological window.

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.

Fluorescent nanothermometers for intracellular thermal sensing.

The importance of high-resolution intracellular thermal sensing and imaging in the field of modern biomedicine has boosted the development of novel nanosized fluorescent systems (fluorescent nanothermometers) as the next generation of probes for intracellular thermal sensing and imaging. This thermal mapping requires fluorescent nanothermometers with good biocompatibility and high thermal sensitivity in order to obtain submicrometric and subdegree spatial and thermal resolutions, respectively. This review describes the different nanosized systems used up to now for intracellular thermal sensing and imaging. We also include the later advances in molecular systems based on fluorescent proteins for thermal mapping. A critical overview of the state of the art and the future perspective is also included.

Bio-functionalization of ligand-free upconverting lanthanide doped nanoparticles for bio-imaging and cell targeting.

We report on the functionalization of ligand-free NaGdF(4):Er(3+), Yb(3+) upconverting nanoparticles with heparin and basic fibroblast growth factor (bFGF). These upconverting nanoparticles are used to obtain high-contrast images of HeLa cells. These images reveal that the heparin-bFGF functionalized nanoparticles show specific binding to the cell membrane.

High resolution fluorescence imaging of cancers using lanthanide ion-doped upconverting nanocrystals.

During the last decade inorganic luminescent nanoparticles that emit visible light under near infrared (NIR) excitation (in the biological window) have played a relevant role for high resolution imaging of cancer. Indeed, semiconductor quantum dots (QDs) and metal nanoparticles, mostly gold nanorods (GNRs), are already commercially available for this purpose. In this work we review the role which is being played by a relatively new class of nanoparticles, based on lanthanide ion doped nanocrystals, to target and image cancer cells using upconversion fluorescence microscopy. These nanoparticles are insulating nanocrystals that are usually doped with small percentages of two different rare earth (lanthanide) ions: The excited donor ions (usually Yb3+ ion) that absorb the NIR excitation and the acceptor ions (usually Er3+, Ho3+ or Tm3+), that are responsible for the emitted visible (or also near infrared) radiation. The higher conversion efficiency of these nanoparticles in respect to those based on QDs and GNRs, as well as the almost independent excitation/emission properties from the particle size, make them particularly promising for fluorescence imaging. The different approaches of these novel nanoparticles devoted to "in vitro" and "in vivo" cancer imaging, selective targeting and treatment are examined in this review.

Nanoparticles for highly efficient multiphoton fluorescence bioimaging.

In this paper, we demonstrate for the first time that the new class of fluoride-based inorganic upconverting nanoparticles, NaYF4:Er3+, Yb3+, are the most efficient multiphoton excited fluorescent nanoparticles developed to date. The near-infrared-to-visible conversion efficiency of the aforementioned nanoparticles surpasses that of CdSe quantum dots and gold nanorods, which are the commercially available inorganic fluorescent nanoprobes presently used for multiphoton fluorescence bioimaging. The results presented here open new perspectives for the implementation of fluorescence tomography by multiphoton fluorescence imaging.

CdSe quantum dots for two-photon fluorescence thermal imaging.

The technological development of quantum dots has ushered in a new era in fluorescence bioimaging, which was propelled with the advent of novel multiphoton fluorescence microscopes. Here, the potential use of CdSe quantum dots has been evaluated as fluorescent nanothermometers for two-photon fluorescence microscopy. In addition to the enhancement in spatial resolution inherent to any multiphoton excitation processes, two-photon (near-infrared) excitation leads to a temperature sensitivity of the emission intensity much higher than that achieved under one-photon (visible) excitation. The peak emission wavelength is also temperature sensitive, providing an additional approach for thermal imaging, which is particularly interesting for systems where nanoparticles are not homogeneously dispersed. On the basis of these superior thermal sensitivity properties of the two-photon excited fluorescence, we have demonstrated the ability of CdSe quantum dots to image a temperature gradient artificially created in a biocompatible fluid (phosphate-buffered saline) and also their ability to measure an intracellular temperature increase externally induced in a single living cell.

Intracellular imaging of HeLa cells by non-functionalized NaYF4 : Er3+, Yb3+ upconverting nanoparticles.

We report on the efficient incorporation of non-functionalized NaYF(4) : Er(3+), Yb(3+) nanoparticles inside HeLa live cancer cells by direct endocytosis. The efficient two-photon excited near-infrared-to-visible upconversion fluorescence of these nanoparticles is then used to obtain high-contrast intracellular fluorescence images of single cells. These images reveal a redistribution of the nanoparticles inside the cell as the incubation time increases. Thus, non-functionalized NaYF(4) : Er(3+), Yb(3+) nanoparticles emerge as very promising fluorescence probes for real-time imaging of cellular dynamics.

Micro-Raman characterization of Zn-diffused channel waveguides in Tm(3+):LiNbO(3).

In this work micro-Raman scattering experiments have been performed in LiNbO(3):Tm(3+) samples with waveguides fabricated by Zn(2+) in-diffusion. The results shown that Zn(2+) ions enter the lattice in Li(+) sites, but also in interstitial positions. This produces a compaction of the lattice close to the surface of the sample, generating the waveguide. It is shown that this region is surrounded by a different area in which the lattice is relaxed to recover the characteristic lattice parameters of LiNbO(3):Tm(3+).