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1.
Biomedicines ; 10(8)2022 Aug 05.
Article in English | MEDLINE | ID: mdl-36009439

ABSTRACT

A great variety of particles of different compositions and shapes with typical sizes in the range 1-200 nm have been developed during the first years of this century [...].

2.
Nanoscale ; 12(23): 12561-12567, 2020 Jun 18.
Article in English | MEDLINE | ID: mdl-32500872

ABSTRACT

Although the motion of a single nanoparticle suspended in a fluid can be easily modeled, things get complicated for non-infinitely diluted systems. Coincidentally, these are the systems of interest in relevant fields such as, nanomedicine, microfluidics and miniaturized energy storage devices. Hence, a better understanding of the dynamics of colloidal nanoparticles is utterly needed. Herein, the motion of colloidal suspension of plasmonic nanoparticles (i.e., gold nanoshells) is investigated via laser speckle imaging. The method relies on the analysis of the speckle pattern generated by colloidal suspensions forced to flow at specific velocities. Temperature-dependent measurements corroborated that the dynamics of non-infinitely diluted nanoparticle suspensions are better described through a diffusive model rather than by the equipartition theorem. Under the tested experimental conditions, an average diffusion velocity between 0.37 and 1.57 mm s-1 was found. Most importantly, these values were largely dependent on the nanoparticle concentration. These results are in agreement with previous reports and indicate the existence of long-range interactions between nanoparticles.

3.
Small ; 12(39): 5394-5400, 2016 Oct.
Article in English | MEDLINE | ID: mdl-27552716

ABSTRACT

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.


Subject(s)
Gold/chemistry , Imaging, Three-Dimensional/methods , Mammary Glands, Animal/anatomy & histology , Nanotubes/chemistry , Neodymium/chemistry , Temperature , Animals , Chickens , Female , Fluorescence , Infrared Rays
4.
Adv Mater ; 28(12): 2421-6, 2016 Mar 23.
Article in English | MEDLINE | ID: mdl-26821941

ABSTRACT

3D optical manipulation of a thermal-sensing upconverting particle allows for the determination of the extension of the thermal gradient created in the surroundings of a plasmonic-mediated photothermal-treated HeLa cancer cell.


Subject(s)
Nanoparticles/chemistry , Europium/chemistry , Fluorides/chemistry , Gold/chemistry , HeLa Cells , Humans , Lasers , Microscopy, Electron, Scanning , Microscopy, Fluorescence , Nanoparticles/metabolism , Nanotubes/chemistry , Temperature , Ytterbium/chemistry , Yttrium/chemistry
5.
Adv Mater ; 27(32): 4781-7, 2015 Aug 26.
Article in English | MEDLINE | ID: mdl-26174612

ABSTRACT

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.


Subject(s)
Nanocomposites/chemistry , Nanotechnology/methods , Thermometers , Lactic Acid/chemistry , Luminescent Measurements , Nanoparticles/chemistry , Neodymium/chemistry , Polyglycolic Acid/chemistry , Polylactic Acid-Polyglycolic Acid Copolymer , Quantum Dots/chemistry , Temperature
6.
Nanomedicine (Lond) ; 9(7): 1047-62, 2014 May.
Article in English | MEDLINE | ID: mdl-24978463

ABSTRACT

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.


Subject(s)
Nanoparticles/chemistry , Nanotechnology/methods , Thermometers , Temperature
7.
Small ; 10(6): 1141-54, 2014 Mar 26.
Article in English | MEDLINE | ID: mdl-24123958

ABSTRACT

The future perspective of fluorescence imaging for real in vivo application are based on novel efficient nanoparticles which is able to emit in the second biological window (1000-1400 nm). In this work, the potential application of Nd(3+) -doped LaF(3) (Nd(3+) :LaF(3) ) nanoparticles is reported for fluorescence bioimaging in both the first and second biological windows based on their three main emission channels of Nd(3+) ions: (4) F(3/2) →(4) I(9/2) , (4) F(3/2) →(4) I(11/2) and (4) F(3/2) →(4) I(13/2) that lead to emissions at around 910, 1050, and 1330 nm, respectively. By systematically comparing the relative emission intensities, penetration depths and subtissue optical dispersion of each transition we propose that optimum subtissue images based on Nd(3+) :LaF(3) nanoparticles are obtained by using the (4) F3/2 →(4) I11/2 (1050 nm) emission band (lying in the second biological window) instead of the traditionally used (4) F(3/2) →(4) I(9/2) (910 nm, in the first biological window). After determining the optimum emission channel, it is used to obtain both in vitro and in vivo images by the controlled incorporation of Nd(3+) :LaF(3) nanoparticles in cancer cells and mice. Nd(3+) :LaF(3)nanoparticles thus emerge as very promising fluorescent nanoprobes for bioimaging in the second biological window.


Subject(s)
Diagnostic Imaging/methods , Fluorides , Lanthanum , Nanoparticles , Neodymium , Absorption , Administration, Intravenous , Animals , Cell Survival , Chickens , Fluorescence , Fluorides/administration & dosage , HeLa Cells , Humans , Injections, Subcutaneous , Lanthanum/administration & dosage , Mice , Nanoparticles/administration & dosage , Nanoparticles/ultrastructure , Neodymium/administration & dosage , Optical Imaging , Particle Size , Solutions
9.
Nanoscale ; 5(17): 7882-9, 2013 Sep 07.
Article in English | MEDLINE | ID: mdl-23852326

ABSTRACT

Quantum dot based-thermometry, in combination with double beam confocal microscopy and infrared thermal imaging, has been used to investigate the heating efficiency of multi-walled carbon nanotubes (MWCNTs) under optical excitation within the first (808 nm) and second (1090 nm) biological windows as well as in the spectral region separating them (980 nm). It has been found that for the three excitation wavelengths the heating efficiency of MWCNTs (10 nm in diameter and 1.5 µm in length) is close to 50%. Despite this "flat" heating efficiency, we have found that the excitation wavelength is, indeed, critical during in vivo experiments due to the spectral dependence of both tissue absorption and scattering coefficients. It has been concluded that efficiency and selectivity of in vivo photothermal treatments based on MWCNTs are simultaneously optimized when laser irradiation lies within the first or second biological window.

10.
Small ; 9(12): 2162-70, 2013 Jun 24.
Article in English | MEDLINE | ID: mdl-23401166

ABSTRACT

Laser-induced thermal effects in optically trapped microspheres and single cells are investigated by quantum dot luminescence thermometry. Thermal spectroscopy has revealed a non-localized temperature distribution around the trap that extends over tens of micrometers, in agreement with previous theoretical models besides identifying water absorption as the most important heating source. The experimental results of thermal loading at a variety of wavelengths reveal that an optimum trapping wavelength exists for biological applications close to 820 nm. This is corroborated by a simultaneous analysis of the spectral dependence of cellular heating and damage in human lymphocytes during optical trapping. This quantum dot luminescence thermometry demonstrates that optical trapping with 820 nm laser radiation produces minimum intracellular heating, well below the cytotoxic level (43 °C), thus, avoiding cell damage.

11.
Nanomedicine (Lond) ; 8(3): 379-88, 2013 Mar.
Article in English | MEDLINE | ID: mdl-23199286

ABSTRACT

AIM: This article demonstrates how controlled hyperthermia at the cellular level can be achieved. MATERIALS & METHODS: The method is based on the simultaneous intracellular incorporation of fluorescence nanothermometers (CdSe quantum dots) and metallic nanoheaters (gold nanorods). RESULTS: Real-time spectral analysis of the quantum dot emission provides a detailed feedback about the intracellular thermal loading caused by gold nanorods excited at the plasmon frequency. Based on this approach, thermal dosimetry is assessed in such a way that the infrared laser (heating) power required to achieve catastrophic intracellular temperature increments in cancer cells is identified. CONCLUSIONS: This pure optical method emerges as a new and promising guide for the development of infrared hyperthermia therapies with minimal invasiveness.


Subject(s)
Cell Physiological Phenomena , Fever , Nanotechnology , Thermometers , Cadmium Compounds/chemistry , Fluorescence , Gold/chemistry , HeLa Cells , Humans , Nanotubes/chemistry , Quantum Dots , Selenium Compounds/chemistry
12.
Nanoscale ; 4(12): 3647-50, 2012 Jun 21.
Article in English | MEDLINE | ID: mdl-22617960

ABSTRACT

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.


Subject(s)
Contrast Media/chemistry , Lanthanoid Series Elements/chemistry , Metal Nanoparticles/chemistry , Apoptosis/drug effects , Cell Membrane/metabolism , Contrast Media/toxicity , Fibroblast Growth Factor 2/metabolism , HeLa Cells , Heparin/metabolism , Humans , Ligands , Metal Nanoparticles/toxicity , Microscopy, Fluorescence , Protein Binding
13.
Cancers (Basel) ; 4(4): 1067-105, 2012 Oct 22.
Article in English | MEDLINE | ID: mdl-24213500

ABSTRACT

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.

14.
ACS Nano ; 5(11): 8665-71, 2011 Nov 22.
Article in English | MEDLINE | ID: mdl-21957870

ABSTRACT

In this study, we report on the remarkable two-photon excited fluorescence efficiency in the "biological window" of CaF(2):Tm(3+),Yb(3+) nanoparticles. On the basis of the strong Tm(3+) ion emission (at around 800 nm), tissue penetration depths as large as 2 mm have been demonstrated, which are more than 4 times those achievable based on the visible emissions in comparable CaF(2):Er(3+),Yb(3+) nanoparticles. The outstanding penetration depth, together with the fluorescence thermal sensitivity demonstrated here, makes CaF(2):Tm(3+),Yb(3+) nanoparticles ideal candidates as multifunctional nanoprobes for high contrast and highly penetrating in vivo fluorescence imaging applications.


Subject(s)
Calcium Fluoride/chemistry , Infrared Rays , Molecular Imaging/methods , Nanoparticles/chemistry , Photons , Thulium/chemistry , Ytterbium/chemistry , Cell Survival/drug effects , Fluorescent Dyes/chemistry , Fluorescent Dyes/toxicity , HeLa Cells , Humans , Materials Testing , Mesenchymal Stem Cells/cytology , Mesenchymal Stem Cells/drug effects , Nanoparticles/toxicity , Particle Size , Spectrometry, Fluorescence
16.
Opt Express ; 18(23): 23544-53, 2010 Nov 08.
Article in English | MEDLINE | ID: mdl-21164698

ABSTRACT

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.


Subject(s)
Imaging, Three-Dimensional/methods , Microscopy, Fluorescence, Multiphoton/methods , Nanoparticles/chemistry , Cadmium Compounds/chemistry , Luminescent Measurements , Nanotubes/chemistry , Quantum Dots , Selenium Compounds/chemistry
17.
Nano Lett ; 10(12): 5109-15, 2010 Dec 08.
Article in English | MEDLINE | ID: mdl-21062040

ABSTRACT

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.

18.
Nanoscale ; 2(4): 495-8, 2010 Apr.
Article in English | MEDLINE | ID: mdl-20644749

ABSTRACT

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.


Subject(s)
Erbium/chemistry , Nanoparticles/chemistry , Ytterbium/chemistry , Yttrium/chemistry , HeLa Cells , Humans , Microscopy, Fluorescence
19.
Opt Lett ; 34(9): 1438-40, 2009 May 01.
Article in English | MEDLINE | ID: mdl-19412298

ABSTRACT

We report on the fabrication and characterization of optical-stripe waveguides in neodymium-doped calcium barium niobate (Nd:CBN) crystals by using He ion implantation assisted with a mask. The guided-mode profiles are successfully modeled through numerical simulations. After annealing at 200 degrees C for 30 min, the waveguide propagation loss could be reduced down to ~3 dB/cm. Room-temperature microluminescence and micro-Raman investigations reveal that the crystal bulk features are well preserved in the active volume of the waveguide, suggesting possible applications as integrated photonic devices.

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