Advanced diagnostic procedures are required to satisfy the continuously increasing demands of modern biomedicine while also addressing the need for cost reduction in public health systems. The ...development of infrared luminescence-based techniques for in vivo imaging as reliable alternatives to traditional imaging enables applications with simpler and more cost-effective apparatus. To further improve the information provided by in vivo luminescence images, the design and fabrication of enhanced infrared-luminescent contrast agents is required. In this work, we demonstrate how simple dopant engineering can lead to infrared-emitting rare-earth-doped nanoparticles with tunable (0.1-1.5 ms) and medium-independent luminescence lifetimes. The combination of these tunable nanostructures with time-gated infrared imaging and time domain analysis is employed to obtain multiplexed in vivo images that are used for complex biodistribution studies.
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.
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.
The continuous development of nanotechnology has resulted in the actual possibility of the design and synthesis of nanostructured materials with pre-tailored functionabilities. Nanostructures capable ...of simultaneous heating and local thermal sensing are in strong demand as they would constitute a revolutionary solution to several challenging problems in bio-medicine, including the achievement of real time control during photothermal therapies. Several approaches have been demonstrated to achieve simultaneous heating and thermal sensing at the nanoscale. Some of them lack of sufficient thermal sensitivity and others require complicated synthesis procedures for heterostructure fabrication. In this study, we demonstrate how single core/shell dielectric nanoparticles with a highly Nd(3+) ion doped shell and an Yb(3+),Er(3+) codoped core are capable of simultaneous thermal sensing and heating under an 808 nm single beam excitation. The spatial separation between the heating shell and sensing core provides remarkable values of the heating efficiency and thermal sensitivity, enabling their application in single beam-controlled heating experiments in both aqueous and tissue environments.
Biomedicine is continuously demanding new luminescent materials to be used as optical probes for the acquisition of high resolution, high contrast and high penetration in vivo images. These ...materials, in combination with advanced techniques, could constitute the first step towards new diagnosis and therapy tools. In this work, we report on the synthesis of long lifetime rare-earth-doped fluoride nanoparticles by adopting different strategies: core/shell and dopant engineering. The here developed nanoparticles show intense infrared emission in the second biological window with a long luminescence lifetime close to 1 millisecond. These two properties make the here presented nanoparticles excellent candidates for time-gated infrared optical bioimaging. Indeed, their potential application as optical imaging contrast agents for autofluorescence-free in vivo small animal imaging has been demonstrated, allowing high contrast real-time tracking of gastrointestinal absorption of nanoparticles and transcranial imaging of intracerebrally injected nanoparticles in the murine brain.
The current status of the use of core-shell rare-earth-doped nanoparticles in biomedical applications is reviewed in detail. The different core-shell rare-earth-doped nanoparticles developed so far ...are described and the most relevant examples of their application in imaging, sensing, and therapy are summarized. In addition, the advantages and disadvantages they present are discussed. Finally, a critical opinion of their potential application in real life biomedicine is given.
Water contamination by heavy metals poses a significant threat to human health and to the environment. Cr3+ is a common contaminant in aqueous media; therefore, innovative sensing technologies for ...reliable detection are in demand. In this study, we demonstrate that NaGdF4: Yb3+, Er3+ up-converting nanoparticles can be used as ratiometric luminescence probes to detect low concentrations of Cr3+ contaminating ions in water. Excitation in the near-infrared region provides a fluorescence-based detection method with large depth penetration and is autofluorescence-free. Based on this ability, a paper-based sensor was manufactured in which the incorporated up-converting nanoparticles allowed a limit of detection of Cr3+ ion concentrations as low as 2 nM. This represents a new step towards the practical application of rare-earth-doped nanoparticles in environmental monitoring, addressing the critical need for efficient detection methods of contaminating ions in water.
•Conventional water pollutant measurement often needs functionalized sensing probes or multiple probes.•This work presents a simple method to measure Cr3+ concentration in water using luminescent rare-earth-doped nanoparticles.•Detecting Cr3+ in water with Yb, Er-NPs does not require functionalization or combination with other nanoparticles.•Integrating Yb, Er-NPs into paper substrates enables simple, quick ratiometric paper-based water quality sensors.•The ratiometric paper-based sensors used in this work shows a limit of detection of 2.4 nM.
Breakthroughs in nanotechnology have made it possible to integrate different nanoparticles in one single hybrid nanostructure (HNS), constituting multifunctional nanosized sensors, carriers, and ...probes with great potential in the life sciences. In addition, such nanostructures could also offer therapeutic capabilities to achieve a wider variety of multifunctionalities. In this work, the encapsulation of both magnetic and infrared emitting nanoparticles into a polymeric matrix leads to a magnetic-fluorescent HNS with multimodal magnetic-fluorescent imaging abilities. The magnetic-fluorescent HNS are capable of simultaneous magnetic resonance imaging and deep tissue infrared fluorescence imaging, overcoming the tissue penetration limits of classical visible-light based optical imaging as reported here in living mice. Additionally, their applicability for magnetic heating in potential hyperthermia treatments is assessed.
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