A mechanoluminescent material, ZnS:Mn,Li, with enhanced brightness for visualizing dental occlusion.

Mechanoluminescent materials are characterized by high luminescence intensity, high repeatability, no external voltage activation, and a good linear relationship between stress and mechanoluminescence intensity within a certain range. Therefore, mechanoluminescent materials have attracted increasing attention from researchers in the fields of stress sensing, encryption and anti-counterfeiting, structural health monitoring, energy-saving lighting, intelligent wearable devices, and other fields. In this study, ZnS:Mn powders with different Mn2+ ratios and different ion doping were synthesized by a high-temperature solid-phase reaction, and the synthesis of various materials was characterized. Then, the optimal mechanoluminescence effect of the ZnS:1%Mn,1%Li material was obtained. The photoluminescence intensity of ZnS:1%Mn,1%Li was 16.7 times higher than that of the sample without doping with Li+, and the mechanoluminescence intensity was 1.64 times higher. Finally, polyethylene terephthalate (PET) film was combined with ZnS:Mn,Li mechanoluminescent powders to prepare flexible three-layer composite film. Based on this, a feasible strategy for the detection of temporomandibular disorders was proposed. The composite film is easy to use, economical, and safe, and has good mechanoluminescent performance, which has potential application value in the field of occlusal force detection and visualization.

Degradable pH-responsive NIR-II imaging probes based on a polymer-lanthanide composite for chemotherapy.

In this research, a pH-sensitive degradable nanoprobe was designed by combining hydrophobic rare earth nanoparticles with biocompatible mPEG-PLGA nanomicelles for near infrared II (NIR-II) imaging-guided anti-tumor chemotherapy. The as-synthesized nanoprobes (about 300 nm) with a highly enhanced permeability and retention (EPR) effect show great potential in the diagnosis of solid tumors, providing new prospects for clinical tumor diagnosis. Then, the degradable composite probes increase the imaging sensitivity of the probe and allow for the slow release of the internal anti-tumor drugs, reducing the loss of the drug during delivery. Finally, ultra-small rare earth nanoparticles (about 6 nm) can be excreted after hydrolysis of the composite probe to reduce the enrichment of the inorganic nanoparticles in vivo. Thus, this degradable NIR-II imaging probe based on a polymer-lanthanide composite could be a promising candidate for preclinical cancer chemotherapy and surgery navigation under a single 808 nm laser.

Hyperthermia and Controllable Free Radical Coenhanced Synergistic Therapy in Hypoxia Enabled by Near-Infrared-II Light Irradiation.

Tumor cell metabolism and tumor blood vessel proliferation are distinct from normal cells. The resulting tumor microenvironment presents a characteristic of hypoxia, which greatly limits the generation of oxygen free radicals and affects the therapeutic effect of photodynamic therapy. Here, we developed an oxygen-independent free radical generated nanosystem (CuFeSe2-AIPH@BSA) with dual-peak absorption in both near-infrared (NIR) regions and utilized it for imaging-guided synergistic treatment. The special absorption provides the nanosystem with high photothermal conversion efficiency and favorably matched photoactivity in both I and II NIR biological windows. Upon NIR light irradiation, the generated heat could prompt AIPH release and decompose to produce oxygen-independent free radicals for killing cancer cells effectively. The contrastive research results show that the enhanced therapeutic efficacy of NIR-II over NIR-I is principally due to its deeper tissue penetration and higher maximum permission exposure that benefits from a longer wavelength. Hyperthermia effect and the production of toxic free radicals upon NIR-II laser illumination are extremely effective in triggering apoptosis and death of cancer cells in the tumor hypoxia microenvironment. The high biocompatibility and excellent anticancer efficiency of CuFeSe2-AIPH@BSA allow it to be an ideal oxygen-independent nanosystem for imaging-guided and NIR-II-mediated synergistic therapy via systemic administration.

Dopamine-mediated photothermal theranostics combined with up-conversion platform under near infrared light.

An organic-inorganic hybrid core-shell nanostructure, based on mesoporous silica coated upconversion core-shell nanoparticles (NaGdF4:Yb,Er@NaGdF4:Yb@mSiO2-Dopa abbreviated here as UCNP@mSiO2-Dopa) that stably incorporates dopamine (Dopa) in the silica layer was introduced as a theranostic nanoplatform for optical imaging guided photothermal therapy (PTT) using NIR excitation. Silica-attaching polyethylenimine make the Dopa transforms into an active form (transferred Dopa) that strongly absorbs light under single 980 nm irradiation. We show that the activated UCNP@mSiO2-Dopa nanoplatform is able to produce a pronounced photothermal effect, that elevates water temperature from room temperature to 41.8 °C within 2 minutes, while concurrently emitting strong upconverted luminescence (UCL) for visualized guidance under 980 nm laser. In addition, we demonstrate the application of the same UCNP@mSiO2-Dopa nanoplatform for magnetic resonance imaging (MRI) and x-ray computed tomography (CT) enabled by the gadolinium (Gd) element contained in the UCNP. Importantly, the in vitro and in vivo anti-cancer therapeutic effects have been shown efficacious, implying the use of the described nanoplatform as an effective multi-modal imaging enabled PTT agent. Results from the in vivo biodistribution of UCNPs@mSiO2, cellular live/dead assay, and histologic analysis of main organs of treated mice, reveal that the UCNP@mSiO2-Dopa agents are bio-compatible with low toxicity.

A cheap and facile route to synthesize monodisperse magnetic nanocrystals and their application as MRI agents.

A facile solution-based thermal decomposition strategy, using very cheap polyisobutylene succimide (PIBSI) and paraffin oil as a surfactant and solvent, respectively, has been developed for the controllable synthesis of magnetic MnFe2O4 and CoFe2O4 nanocrystals (NCs) with high dispersibility, uniform shape, and high yield. By fine-tuning the reaction temperature and growth time, the morphology and size of MnFe2O4 and CoFe2O4 NCs can be simply regulated. It is found that the surfactant PIBSI plays a key role in the final shape of the products due to its long chain with non-polar groups, which can markedly hinder the aggregation of the NCs and thus greatly improve the stability and dispersibility of the products. The results reveal that MnFe2O4 and CoFe2O4 NCs have good biocompatibility and obvious T2 contrast enhancement effects have been achieved with the increase of iron concentration. MnFe2O4 and CoFe2O4 NCs show high longitudinal relaxivity of 165.6 and 65.143 mM(-1) S(-1) in aqueous solutions due to the positive signal enhancement ability of Fe(3+) ions, indicating the highly potential to be used as effective T2 contrast agents for magnetic resonance imaging (MRI).

An imaging-guided platform for synergistic photodynamic/photothermal/chemo-therapy with pH/temperature-responsive drug release.

To integrate biological imaging and multimodal therapies into one platform for enhanced anti-cancer efficacy, we have designed a novel core/shell structured nano-theranostic by conjugating photosensitive Au25(SR)18 - (SR refers to thiolate) clusters, pH/temperature-responsive polymer P(NIPAm-MAA), and anti-cancer drug (doxorubicin, DOX) onto the surface of mesoporous silica coated core-shell up-conversion nanoparticles (UCNPs). It is found that the photodynamic therapy (PDT) derived from the generated reactive oxygen species and the photothermal therapy (PTT) arising from the photothermal effect can be simultaneously triggered by a single 980 nm near infrared (NIR) light. Furthermore, the thermal effect can also stimulate the pH/temperature sensitive polymer in the cancer sites, thus realizing the targeted and controllable DOX release. The combined PDT, PTT and pH/temperature responsive chemo-therapy can markedly improve the therapeutic efficacy, which has been confirmed by both in intro and in vivo assays. Moreover, the doped rare earths endow the platform with dual-modal up-conversion luminescent (UCL) and computer tomography (CT) imaging properties, thus achieving the target of imaging-guided synergistic therapy under by a single NIR light.