Unlocking Single-Particle Multiparametric Sensing: Decoupling Temperature and Viscosity Readouts through Upconverting Polarized Spectroscopy.

Upconverting particles (UCPs), renowned for their capability to convert infrared to visible light, serve as invaluable imaging probes. Furthermore, their responsiveness to diverse external stimuli holds promise for leveraging UCPs as remote multiparametric sensors, capable of characterizing medium properties in a single assessment. However, the utility of UCPs in multiparametric sensing is impeded by crosstalk, wherein distinct external stimuli induce identical alterations in UCP luminescence, hindering accurate interpretation, and yielding erroneous outputs.

Finite element modeling of plasmonic resonances in photothermal gold nanoparticles embedded in cells.

The use of plasmonic nanoparticles in performing photothermal treatments in cancer cells requires a full knowledge about their optical properties. The surface plasmon resonance is easily foreseen and measurable in colloidal suspensions, however it can be strongly modified when located inside cells. Assessing the optical behavior of plasmonic nanoparticles in cells is essential for an efficient and controlled treatment.

Synergistic Enhancement of Photodynamic Cancer Therapy with Mesenchymal Stem Cells and Theranostic Nanoparticles.

Nanoparticles engineered to combat cancer and other life-threatening diseases may significantly improve patient outcomes. However, inefficient nanoparticle delivery to tumors limits their use and necessitates the development of complex delivery approaches. Here, we examine this issue by harnessing the tumor-homing abilities of human mesenchymal stem cells (MSCs) to deliver a decoupled theranostic complex of rare earth-doped nanoparticles (dNPs) and photosensitizer chlorin e6 (Ce6) to tumors.

New Insights in Luminescence and Quenching Mechanisms of AgS Nanocrystals through Temperature-Dependent Spectroscopy.

Bright near-infrared-emitting AgS nanocrystals (NCs) are used for in vivo temperature sensing relying on a reversible variation in intensity and photoluminescence lifetime within the physiological temperature range. Here, to gain insights into the luminescence and quenching mechanisms, we investigated the temperature-dependent luminescence of AgS NCs from 300 to 10 K. Interestingly, both emission and lifetime measurements reveal similar and strong thermal quenching from 200 to 300 K, indicating an intrinsic quenching process that limits the photoluminescence quantum yield at room temperature, even for perfectly passivated NCs.

Influence of SPION Surface Coating on Magnetic Properties and Theranostic Profile.

This study aimed to develop multifunctional nanoplatforms for both cancer imaging and therapy using superparamagnetic iron oxide nanoparticles (SPIONs). Two distinct synthetic methods, reduction-precipitation (M) and co-precipitation at controlled pH (M), were explored, including the assessment of the coating's influence, namely dextran and gold, on their magnetic properties. These SPIONs were further functionalized with gadolinium to act as dual T1/T2 contrast agents for magnetic resonance imaging (MRI).

Brownian Motion Governs the Plasmonic Enhancement of Colloidal Upconverting Nanoparticles.

Upconverting nanoparticles are essential in modern photonics due to their ability to convert infrared light to visible light. Despite their significance, they exhibit limited brightness, a key drawback that can be addressed by combining them with plasmonic nanoparticles. Plasmon-enhanced upconversion has been widely demonstrated in dry environments, where upconverting nanoparticles are immobilized, but constitutes a challenge in liquid media where Brownian motion competes against immobilization.

Early in vivo detection of denervation-induced atrophy by luminescence transient nanothermometry.

Denervation induces skeletal muscle atrophy due to the loss of control and feedback with the nervous system. Unfortunately, muscle atrophy only becomes evident days after the denervation event when it could be irreversible. Alternative diagnosis tools for early detection of denervation-induced muscle atrophy are, thus, required.

Ion-induced bias in AgS luminescent nanothermometers.

Luminescence nanothermometry allows measuring temperature remotely and in a minimally invasive way by using the luminescence signal provided by nanosized materials. This technology has allowed, for example, the determination of intracellular temperature and monitoring of thermal processes in animal models. However, in the biomedical context, this sensing technology is crippled by the presence of bias (cross-sensitivity) that reduces the reliability of the thermal readout.

Neural Networks Push the Limits of Luminescence Lifetime Nanosensing.

Luminescence lifetime-based sensing is ideally suited to monitor biological systems due to its minimal invasiveness and remote working principle. Yet, its applicability is limited in conditions of low signal-to-noise ratio (SNR) induced by, e.g.

Time-Dependent Changes in Muscle IGF1-IGFBP5-PAPP System after Sciatic Denervation.

Denervation-induced muscle atrophy is a frequent cause of skeletal muscle diseases. However, the role of the most important muscle growth factor, insulin-like growth factor (IGF-1), in this process is poorly understood. IGF-1 activity is controlled by six IGF-1 binding proteins (IGFBPs).

Ag S Biocompatible Ensembles as Dual OCT Contrast Agents and NIR Ocular Imaging Probes.

Ag S nanoparticles (NPs) emerge as a unique system that simultaneously features in vivo near-infrared (NIR) imaging, remote heating, and low toxicity thermal sensing. In this work, their capabilities are extended into the fields of optical coherence tomography (OCT), as contrast agents, and NIR probes in both ex vivo and in vivo experiments in eyeballs. The new dual property for ocular imaging is obtained by the preparation of Ag S NPs ensembles with a biocompatible amphiphilic block copolymer.

Spotlight on Luminescence Thermometry: Basics, Challenges, and Cutting-Edge Applications.

Luminescence (nano)thermometry is a remote sensing technique that relies on the temperature dependency of the luminescence features (e.g., bandshape, peak energy or intensity, and excited state lifetimes and risetimes) of a phosphor to measure temperature.

A Generalized Approach to Photon Avalanche Upconversion in Luminescent Nanocrystals.

Photon avalanching nanoparticles (ANPs) exhibit extremely nonlinear upconverted emission valuable for subdiffraction imaging, nanoscale sensing, and optical computing. Avalanching has been demonstrated with Tm-, Pr-, or Nd-doped nanocrystals, but their emission is limited to a few wavelengths and materials. Here, we utilize Gd-assisted energy migration to tune the emission wavelengths of Tm-sensitized ANPs and generate highly nonlinear emission from Eu, Tb, Ho, and Er ions.

Lanthanide doped nanoparticles for reliable and precise luminescence nanothermometry in the third biological window.

In recent years, infrared emitting luminescent nanothermometers have attracted significant attention because their potential for the development of new diagnosis and therapy procedures. Despite their promising applications, concerns have been raised about their reliability due to the spectral distortions induced by tissues that are present even in the commonly used second biological window (1000-1370 nm). In this work, we present an innovative solution to this issue by demonstrating the effectiveness of shifting the operation range of these nanothermometers to the third biological window (1550-1850 nm).

Exploring the Origin of the Thermal Sensitivity of Near-Infrared-II Emitting Rare Earth Nanoparticles.

Rare-earth doped nanoparticles (RENPs) are attracting increasing interest in materials science due to their optical, magnetic, and chemical properties. RENPs can emit and absorb radiation in the second biological window (NIR-II, 1000-1400 nm) making them ideal optical probes for photoluminescence (PL) in vivo imaging. Their narrow emission bands and long PL lifetimes enable autofluorescence-free multiplexed imaging.

3D Optical Coherence Thermometry Using Polymeric Nanogels.

In nanothermometry, the use of nanoparticles as thermal probes enables remote and minimally invasive sensing. In the biomedical context, nanothermometry has emerged as a powerful tool where traditional approaches, like infrared thermal sensing and contact thermometers, fall short. Despite the strides of this technology in preclinical settings, nanothermometry is not mature enough to be translated to the bedside.

Synthesis of novel hybrid mesoporous gold iron oxide nanoconstructs for enhanced catalytic reduction and remediation of toxic organic pollutants.

The development of highly efficient, rapid, and recyclable nanocatalysts for effective elimination of toxic environmental contaminants remains a high priority in various industrial applications. Herein, we report the preparation of hybrid mesoporous gold-iron oxide nanoparticles (Au-IO NPs) the nanocasting "inverse hard-templated replication" approach. Dispersed Au NPs were anchored on amine-functionalized iron oxide incorporated APMS (IO@APMS-amine), followed by etching of the silica template to afford hybrid mesoporous Au-IO NPs.

Tuning Phonon Energies in Lanthanide-doped Potassium Lead Halide Nanocrystals for Enhanced Nonlinearity and Upconversion.

Optical applications of lanthanide-doped nanoparticles require materials with low phonon energies to minimize nonradiative relaxation and promote nonlinear processes like upconversion. Heavy halide hosts offer low phonon energies but are challenging to synthesize as nanocrystals. Here, we demonstrate the size-controlled synthesis of low-phonon-energy KPb X (X=Cl, Br) nanoparticles and the ability to tune nanocrystal phonon energies as low as 128 cm .

Optomagnetic nanofluids for controlled brain hyperthermia: a critical study.

Optomagnetic nanofluids (OMNFs) are colloidal dispersions of nanoparticles (NPs) with combined magnetic and optical properties. They are especially appealing in biomedicine since they can be used as minimally invasive platforms for controlled hyperthermia treatment of otherwise difficultly accessible tumors such as intracranial ones. On the one hand, magnetic NPs act as heating mediators when subjected to alternating magnetic fields or light irradiation.

Near infrared bioimaging and biosensing with semiconductor and rare-earth nanoparticles: recent developments in multifunctional nanomaterials.

Research in novel materials has been extremely active over the past few decades, wherein a major area of interest has been nanoparticles with special optical properties. These structures can overcome some of the intrinsic limitations of contrast agents routinely used in medical practice, while offering additional functionalities. Materials that absorb or scatter near infrared light, to which biological tissues are partially transparent, have attracted significant attention and demonstrated their potential in preclinical research.

Thermoresponsive Polymeric Nanolenses Magnify the Thermal Sensitivity of Single Upconverting Nanoparticles.

Lanthanide-based upconverting nanoparticles (UCNPs) are trustworthy workhorses in luminescent nanothermometry. The use of UCNPs-based nanothermometers has enabled the determination of the thermal properties of cell membranes and monitoring of in vivo thermal therapies in real time. However, UCNPs boast low thermal sensitivity and brightness, which, along with the difficulty in controlling individual UCNP remotely, make them less than ideal nanothermometers at the single-particle level.

Luminescence Thermometry for Brain Activity Monitoring: A Perspective.

Minimally invasive monitoring of brain activity is essential not only to gain understanding on the working principles of the brain, but also for the development of new diagnostic tools. In this perspective we describe how brain thermometry could be an alternative to conventional methods (e.g.

Less is more: dimensionality reduction as a general strategy for more precise luminescence thermometry.

Thermal resolution (also referred to as temperature uncertainty) establishes the minimum discernible temperature change sensed by luminescent thermometers and is a key figure of merit to rank them. Much has been done to minimize its value via probe optimization and correction of readout artifacts, but little effort was put into a better exploitation of calibration datasets. In this context, this work aims at providing a new perspective on the definition of luminescence-based thermometric parameters using dimensionality reduction techniques that emerged in the last years.

Quantitative Comparison of the Light-to-Heat Conversion Efficiency in Nanomaterials Suitable for Photothermal Therapy.

Functional colloidal nanoparticles capable of converting between various energy types are finding an increasing number of applications. One of the relevant examples concerns light-to-heat-converting colloidal nanoparticles that may be useful for localized photothermal therapy of cancers. Unfortunately, quantitative comparison and ranking of nanoheaters are not straightforward as materials of different compositions and structures have different photophysical and chemical properties and may interact differently with the biological environment.