Gold Nanoshell Nanomicelles for Potential Magnetic Resonance Imaging,Light‐Triggered Drug Release,and Photothermal Therapy

A novel multifunctional drug‐delivery platform is developed based on cholesteryl succinyl silane (CSS) nanomicelles loaded with doxorubicin, Fe₃O₄ magnetic nanoparticles, and gold nanoshells (CDF‐Au‐shell nanomicelles) to combine magnetic resonance (MR) imaging, magnetic‐targeted drug delivery, light‐triggered drug release, and photothermal therapy. The nanomicelles show improved drug‐encapsulation efficiency and loading level, and a good response to magnetic fields, even after the formation of the gold nanoshell. An enhancement for T₂‐weighted MR imaging is observed for the CDF‐Au‐shell nanomicelles. These nanomicelles display surface plasmon absorbance in the near‐infrared (NIR) region, thus exhibiting an NIR (808 nm)‐induced temperature elevation and an NIR light‐triggered and stepwise release behavior of doxorubicin due to the unique characteristics of the CSS nanomicelles. Photothermal cytotoxicity in vitro confirms that the CDF‐Au‐shell nanomicelles cause cell death through photothermal effects only under NIR laser irradiation. Cancer cells incubated with CDF‐Au‐shell nanomicelles show a significant decrease in cell viability only in the presence of both NIR irradiation and a magnetic field, which is attributed to the synergetic effects of the magnetic‐field‐guided drug delivery and the photothermal therapy. Therefore, such multicomponent nanomicelles can be developed as a smart and promising nanosystem that integrates multiple capabilities for effective cancer diagnosis and therapy.     

Gd2O(CO3)2 · H2O Particles and the Corresponding Gd2O3: Synthesis and Applications of Magnetic Resonance Contrast Agents and Template Particles for Hollow Spheres and Hybrid Composites

The solution approach was employed to yield multifunctional amorphous Gd₂O(CO₃)₂ · H₂O colloidal spheres by reflux of an aqueous solution containing GdCl₃ · 6H₂O and urea. By elongating the reaction time, crystalline rhombus‐ shaped Gd₂O(CO₃)₂ · H₂O with at least 87% yield could be formed and were also accompanied by some rectangular particles. High‐resolution synchrotron powder X‐ray diffraction provides crystal structure information, such as cell dimensions, and indexes the exact crystal packing with hexagonal symmetry, which is absent from the Joint Committee on Powder Diffraction Standards file, for the crystalline rhombus sample. Particle formation was studied based on the reaction time and the concentration ratio of [urea]/[GdCl₃ · 6H₂O]. After a calcination process, the amorphous spheres and crystalline rhombus Gd₂O(CO₃)₂ · H₂O particles convert into crystalline Gd₂O₃ at temperatures above 600 °C. For in vitro magnetic resonance imaging (MRI), both Gd₂O(CO₃)₂ · H₂O and Gd₂O₃ species show the promising T₁‐ and T₂‐weighted effects and could potentially serve as bimodal T₁‐positive and T₂‐negative contrast agents. The amorphous Gd₂O(CO₃)₂ · H₂O contrast agent further demonstrates enhanced contrast of the liver and kidney using a dynamic contrast‐enhanced MR imaging (DCE‐MRI) technique for in vivo investigation. The multifunctional capability of the amorphous Gd₂O(CO₃)₂ · H₂O spheres was also evidenced by the formation of nanoshells using these amorphous spheres as the template. Surface engineering of the amorphous Gd₂O(CO₃)₂ · H₂O spheres could be performed by covalent bonding to form hollow silica nanoshells and hollow silica@Fe₃O₄ hybrid particles.     

Nucleus‐Targeting Gold Nanoclusters for Simultaneous In Vivo Fluorescence Imaging,Gene Delivery,and NIR‐Light Activated Photodynamic Therapy

The nucleus is one of the most important cellular organelles and molecular anticancer drugs, such as cisplatin and doxorubicin, that target DNA inside the nucleus, are proving to be more effective at killing cancer cells than those targeting at cytoplasm. Nucleus‐targeting nanomaterials are very rare. It is a grand challenge to design highly efficient nucleus‐targeting multifunctional nanomaterials that are able to perform simultaneous bioimaging and therapy for the destruction of cancer cells. Here, unique nucleus‐targeting gold nanoclusters (TAT peptide–Au NCs) are designed to perform simultaneous in vitro and in vivo fluorescence imaging, gene delivery, and near‐infrared (NIR) light activated photodynamic therapy for effective cancer cell killing. Confocal laser scanning microscopy observations reveal that TAT peptide–Au NCs are distributed throughout the cytoplasm region with a significant fraction entering into the nucleus. The TAT peptide–Au NCs can also act as DNA nanocargoes to achieve very high gene transfection efficiencies (≈81%) in HeLa cells and in zebrafish. Furthermore, TAT peptide–Au NCs are also able to sensitize formation of singlet oxygen (¹O₂) without the co‐presence of organic photosensitizers for the destruction of cancer cells upon NIR light photoexcitation.     

NIR‐II Light Activated Photosensitizer with Aggregation‐Induced Emission for Precise and Efficient Two‐Photon Photodynamic Cancer Cell Ablation

Near infrared (NIR) light excitable photosensitizers are highly desirable for photodynamic therapy with deep penetration. Herein, a NIR‐II light (1200 nm) activated photosensitizer TQ‐BTPE is designed with aggregation‐induced singlet oxygen (¹O₂) generation for two‐photon photodynamic cancer cell ablation. TQ‐BTPE shows good two‐photon absorption and bright aggregation‐induced NIR‐I emission upon NIR‐II laser excitation. The ¹O₂ produced by TQ‐BTPE in an aqueous medium is much more efficient than that of commercial photosensitizer Ce6 under white light irradiation. Upon NIR‐II excitation, the two‐photon photosensitization of TQ‐BTPE is sevenfold higher than that of Ce6. The TQ‐BTPE molecules internalized by HeLa cells are mostly located in lysosomes as small aggregate dots with homogeneous distribution inside the cells, which favors efficient photodynamic cell ablation. The two‐photon photosensitization of TQ‐BTPE upon NIR‐I and NIR‐II excitation shows higher ¹O₂ generation efficiency than under NIR‐I excitation owing to the larger two‐photon absorption cross section at 920 nm. However, NIR‐II light exhibits better biological tissue penetration capability after passing through a fresh pork tissue, which facilitates stronger two‐photon photosensitization and better cancer cell ablation performance. This work highlights the promise of NIR‐II light excitable photosensitizers for deep‐tissue photodynamic therapy.     

Boosting H2O2‐Guided Chemodynamic Therapy of Cancer by Enhancing Reaction Kinetics through Versatile Biomimetic Fenton Nanocatalysts and the Second Near‐Infrared Light Irradiation

Fenton reaction–based chemodynamic therapy (CDT) has attracted considerable attention for tumor treatment, because the Fenton reaction can degrade endogenous H₂O₂ within the tumor to form reactive oxygen species (ROS) to kill cancer cells. The kinetics of the Fenton reaction has significantly influenced its treatment efficacy. It is crucial to enhance the reaction kinetics at the maximum H₂O₂ concentration to quickly produce vast amounts of ROS to achieve treatment efficacy, which to date, has not been realized. Herein, reported is an efficacious CDT treatment of breast cancer using biomimetic CS‐GOD@CM nanocatalysts, which are rationally designed to significantly boost the Fenton reaction through improvement of H₂O₂ concentration within tumors, and application of the second near‐infrared (NIR‐II) light irradiation at the maximum concentration, which is monitored by photoacoustic imaging. The biomimetic nanocatalysts are composed of ultra‐small Cu_2?xSe (CS) nanoparticles, glucose oxidase (GOD), and tumor cell membrane (CM). The nanocatalysts can be retained in tumor for more than two days to oxidize glucose and produce an approximately 2.6‐fold increase in H₂O₂ to enhance the Fenton reaction under the NIR‐II irradiation. This work demonstrates for the first time the CDT treatment of cancer enhanced by the NIR‐II light.     

Surface State Mediated NIR Two‐Photon Fluorescence of Iron Oxides for Nonlinear Optical Microscopy

The development of fluorescent iron oxide nanomaterials is highly desired for multimodal molecular imaging. Instead of incorporating fluorescent dyes on the surface of iron oxides, a ligand‐assisted synthesis approach is developed to allow near‐infrared (NIR) fluorescence in Fe₃O₄ nanostructures. Using a trimesic acid (TMA)/citrate‐mediated synthesis, fabricated Fe₃O₄ nanostructures can generate a NIR two‐photon florescence (TPF) peak around 700 nm under the excitation by a 1230‐nm femtosecond laser. By tailoring the absorption of Fe₃O₄ nanostructures toward NIR band, the NIR‐TPF efficiency can be greatly increased. Through internal etching, surface peeling, and ligand replacement, spectroscopic results validated that such resonantly enhanced NIR‐TPF is mediated by surface states with strong NIR‐IR absorption. This TPF signal evolution can be generalized to other iron oxide nanomaterials like magnetite nanoparticles and α‐Fe₂O₃ nanoplates. Using the developed fluorescent Fe₃O₄ nanostructures, it is demonstrated that their TPF and third harmonic generation (THG) contrast in the nonlinear optical microscopy of live cells. It is anticipated that the synthesized NIR photofunctional Fe₃O₄ will serve as a versatile platform for dual‐modality magnetic resonance imaging (MRI) as well as a magnet‐guided theranostic agent.     

Enhanced Antitumor Efficacy by 808 nm Laser‐Induced Synergistic Photothermal and Photodynamic Therapy Based on a Indocyanine‐Green‐Attached W18O49 Nanostructure

A novel nanoplatform based on tungsten oxide (W₁₈O₄₉, WO) and indocyanine green (ICG) for dual‐modal photothermal therapy (PTT) and photodynamic therapy (PDT) has been successfully constructed. In this design, the hierarchical unique nanorod‐bundled W₁₈O₄₉ nanostructures play roles in being not only as an efficient photothermal agent for PTT but also as a potential nanovehicle for ICG molecules via electrostatic adsorption after modified with trimethylammonium groups on their surface. It is found that the ability of ICG to produce cytotoxic reactive oxygen species for PDT is well maintained after being attached on the WO, thus the as‐obtained WO@ICG can achieve a synergistic effect of combined PTT and PDT under single 808 nm near‐infrared (NIR) laser excitation. Notably, compared with PTT or PDT alone, the enhanced HeLa cells lethality of the 808 nm laser triggered dual‐modal therapy is observed. The in vivo animal experiments have shown that WO@ICG has effective solid tumor ablation effect with 808 nm NIR light irradiation, revealing the potential of these nanocomposites as a NIR‐mediated dual‐modal therapeutic platform for cancer treatment.     

Morphological Evolution and Magnetic Property of Rare‐Earth‐Doped Hematite Nanoparticles: Promising Contrast Agents for T1‐Weighted Magnetic Resonance Imaging

A series of uniform rare‐earth‐doped hematite (α‐Fe₂O₃) nanoparticles are synthesized by a facile hydrothermal strategy. In a typical case of gadolinium (Gd)‐doped α‐Fe₂O₃, the morphology and chemical composition can be readily tailored by tuning the initial proportion of Gd³⁺/Fe³⁺ sources. As a result, the products are observed to be stretched into more elongated shapes with an increasing dopant ratio. As a benefit of such an elongated morphological feature and Gd³⁺ ions of larger effective magnetic moment than Fe³⁺, the doped product with the highest ratio of Gd³⁺ at 5.7% shows abnormal ferromagnetic features with a remnant magnetization of 0.605 emu g^?1 and a coercivity value of 430 Oe at 4 K. Density of states calculations also reveal the increase of total magnetic moment induced by Gd³⁺ dopant in α‐Fe₂O₃ hosts, as well as possible change of magnetic arrangement. As‐synthesized Gd‐doped α‐Fe₂O₃ nanoparticles are probed as contrast agents for T1‐weighted magnetic resonance imaging, achieving a remarkable enhancement effect for both in vitro and in vivo tests.     

Design and Synthesis of Multifunctional Drug Carriers Based on Luminescent Rattle‐Type Mesoporous Silica Microspheres with a Thermosensitive Hydrogel as a Controlled Switch

A novel approach for the fabrication of multifunctional microspheres integrating several advantages of mesoporous, luminescence, and temperature responses into one single entity is reported. First, the hollow mesoporous silica capsules are fabricated via a sacrificial template route. Then, Gd₂O₃:Eu³⁺ luminescent nanoparticles are incorporated into the internal cavities to form rattle‐type mesoporous silica nanocapsules by an incipient‐wetness impregnation method. Finally, the rattle‐type capsules serve as a nanoreactor for successfully filling temperature‐responsive hydrogel via photoinduced polymerization to form the multifunctional composite microspheres. The organic–inorganic hybrid microspheres show a red emission under UV irradiation due to the luminescent Gd₂O₃:Eu³⁺ core. The in vitro cytotoxicity tests show that the samples have good biocompatibility, which indicates that the nanocomposite could be a promising candidate for drug delivery. In addition, flow cytometry and confocal laser scanning microscopy (CLSM) confirm that the sample can be effectively taken up by SKOV3 cells. For in vitro magnetic resonance imaging (MRI), the sample shows the promising spin‐lattice relaxation time (T₁) weighted effect and could potentially apply as a T₁‐positive contrast agent. This composite drug delivery system (DDS) provides a positive temperature controlled “on‐off”drug release pattern and the drug, indomethacin (IMC), is released fast at 45 °C (on phase) and completely shut off at 20 °C (off phase). Meanwhile Gd₂O₃:Eu³⁺ plays an important role as the luminescent tag for tracking the drug loading and release process by the reversible luminescence quenching and recovery phenomenon. These results indicate that the obtained multifunctional composite has the potential to be used as a smart DDS for biomedical applications.     

An Acceptor–Donor–Acceptor Structured Small Molecule for Effective NIR Triggered Dual Phototherapy of Cancer

Dual phototherapy, including photodynamic therapy (PDT) and photothermal therapy (PTT), is regarded as a more effective method for cancer treatment than single PDT or PTT. However, development of single component and near‐infrared (NIR) triggered agents for efficient dual phototherapy remains a challenge. Herein, a simple strategy to develop dual‐functional small‐molecules‐based photosensitizers for combined PDT and PTT treatment is proposed through: 1) finely modulating HOMO–LUMO energy levels to regulate the intersystem crossing (ISC) process for effective singlet oxygen (¹O₂) generation for PDT; 2) effectively inhibiting fluorescence via strong intramolecular charge transfer (ICT) to maximize the conversion of photo energy to heat for PTT or ISC process for PDT. An acceptor–donor–acceptor (A‐D‐A) structured small molecule (CPDT) is designed and synthesized. The biocompatible nanoparticles, FA‐CNPs, prepared by encapsulating CPDT directly with a folate functionalized amphipathic copolymer, present strong NIR absorption, robust photostability, cancer cell targeting, high photothermal conversion efficiency as well as efficient ¹O₂ generation under single 808 nm laser irradiation. Furthermore, synergistic PDT and PTT effects of FA‐CNPs in vivo are demonstrated by significant inhibition of tumor growth. The proposed strategy may provide a new approach to reasonably design and develop safe and efficient photosensitizers for dual phototherapy against cancer.     

A New Single 808 nm NIR Light‐Induced Imaging‐Guided Multifunctional Cancer Therapy Platform

The NIR light‐induced imaging‐guided cancer therapy is a promising route in the targeting cancer therapy field. However, up to now, the existing single‐modality light‐induced imaging effects are not enough to meet the higher diagnosis requirement. Thus, the multifunctional cancer therapy platform with multimode light‐induced imaging effects is highly desirable. In this work, captopril stabilized‐Au nanoclusters Au₂₅(Capt)₁₈?(Au₂₅) are assembled into the mesoporous silica shell coating outside of Nd³⁺‐sensitized upconversion nanoparticles (UCNPs) for the first time. The newly formed Au₂₅ shell exhibits considerable photothermal effects, bringing about the photothermal imaging and photoacoustic imaging properties, which couple with the upconversion luminescence imaging. More importantly, the three light‐induced imaging effects can be simultaneously achieved by exciting with a single NIR light (808 nm), which is also the triggering factor for the photothermal and photodynamic cancer therapy. Besides, the nanoparticles can also present the magnetic resonance and computer tomography imaging effects due to the Gd³⁺ and Yb³⁺ ions in the UCNPs. Furthermore, due to the photodynamic and the photothermal effects, the nanoparticles possess efficient in vivo tumor growth inhibition under the single irradiation of 808 nm light. The multifunctional cancer therapy platform with multimode imaging effects realizes a true sense of light‐induced imaging‐guided cancer therapy.     

Controllable Generation of Nitric Oxide by Near‐Infrared‐Sensitized Upconversion Nanoparticles for Tumor Therapy

NaYbF₄:Tm@NaYF₄:Yb/Er upconversion nanoparticles are synthesized and then integrated with light‐sensitive nitric oxide (NO) donors (Roussin's black salt) to construct a novel near‐infrared (NIR)‐triggered on‐demand NO delivery platform. This nanocompound can absorb 980 nm NIR photons, convert them into higher energy photons and then transfer the energy to the NO donors, resulting in an efficient release of NO. By manipulating the output power of the 980‐nm NIR light, NO‐concentration‐dependent biological effects for cancer therapy can be fine‐tuned, which is investigated and confirmed in vitro. High concentrations of NO can directly kill cancer cells and low concentrations of NO can act as a potent P‐glycoprotein (P‐gp) modulator to overcome multi‐drug resistance (MDR) if combined with chemotherapy.     

Photo‐ and pH‐Triggered Release of Anticancer Drugs from Mesoporous Silica‐Coated Pd@Ag Nanoparticles

A smart drug delivery system integrating both photothermal therapy and chemotherapy for killing cancer cells is reported. The delivery system is based on a mesoporous silica‐coated Pd@Ag nanoplates composite. The Pd@Ag nanoplate core can effectively absorb and convert near infrared (NIR) light into heat. The mesoporous silica shell is provided as the host for loading anticancer drug, doxorubicin (DOX). The mesoporous shell consists of large pores, ～10 nm in diameter, and allows the DOX loading as high as 49% in weight. DOX loaded core–shell nanoparticles exhibit a higher efficiency in killing cancer cells than free DOX. More importantly, DOX molecules are loaded in the mesopores shell through coordination bonds that are responsive to pH and heat. The release of DOX from the core‐shell delivery vehicles into cancer cells can be therefore triggered by the pH drop caused by endocytosis and also NIR irradiation. A synergistic effect of combining chemotherapy and photothermal therapy is observed in our core‐shell drug delivery system. The cell‐killing efficacy by DOX‐loaded core–shell particles under NIR irradiation is higher than the sum of chemotherapy by DOX‐loaded particles and photothermal therapy by core–shell particles without DOX.     

Rattle‐Type Fe3O4@CuS Developed to Conduct Magnetically Guided Photoinduced Hyperthermia at First and Second NIR Biological Windows

A therapeutic carrier in the second near‐infrared (NIR) window is created that features magnetic target, magnetic resonance imaging (MRI) diagnosis, and photothermal therapy functions through the manipulation of a magnet and NIR laser. A covellite‐based CuS in the form of rattle‐type Fe₃O₄@CuS nanoparticles is developed to conduct photoinduced hyperthermia at 808 and 1064 nm of the first and second NIR windows, respectively. The Fe₃O₄@CuS nanoparticles exhibit broad NIR absorption from 700 to 1300 nm. The in vitro photothermal results show that the laser intensity obtained using 808 nm irradiation required a twofold increase in its magnitude to achieve the same damage in cells as that obtained using 1064 nm irradiation. Because of the favorable magnetic property of Fe₃O₄, magnetically guided photothermal tumor ablation is performed for assessing both laser exposures. According to the results under the fixed laser intensity and irradiation spot, exposure to 1064 nm completely removed tumors showing no signs of relapse. On the other hand, 808 nm irradiation leads to effective inhibition of growth that remained nearly unchanged for up to 30 d, but the tumors are not completely eliminated. In addition, MRI is performed to monitor rattle‐type Fe₃O₄@CuS localization in the tumor following magnetic attraction.     

NIR Light‐Triggered Degradable MoTe2 Nanosheets for Combined Photothermal and Chemotherapy of Cancer

Telluride molybdenum (MoTe₂) nanosheets with wide near‐infrared (NIR) absorbance are functionalized with polyethylene glycol‐cyclic arginine‐glycine‐aspartic acid tripeptide (PEG‐cRGD). After loading a chemotherapeutic drug (doxorubicin, DOX), MoTe₂‐PEG‐cRGD/DOX is used for combined photothermal therapy and chemotherapy. With the high photothermal conversion efficiency, MoTe₂‐PEG‐cRGD/DOX exhibits favorable cells killing ability under NIR irradiation. Owing to the cRGD‐mediated specific tumor targeting, MoTe₂‐PEG‐cRGD/DOX shows efficient accumulation in tumors to induce a strong tumor ablation effect. MoTe₂‐PEG‐cRGD nanosheets, which are relatively stable in the circulation, could be degraded under NIR ray. The in vitro and in vivo experimental results demonstrate that this theranostic nanoagent, which could accumulate in tumors to allow photothermal imaging and combined therapy, is readily degradable in normal organs to enable rapid excretion and avoid long‐term retention/toxicity, holding great potential to treat tumor effectively.     

Nonoxidized MXene Quantum Dots Prepared by Microexplosion Method for Cancer Catalytic Therapy

Nanocatalysts based on Fenton or Fenton‐like reactions for amplification of intracellular oxidative stress has become a frontier research area of tumor precise therapy. However, the major translational challenges are low catalytic efficiency, poor biocompatibility, and even potential toxicities. Here, a Ti‐based material with excellent biocompatibility is proposed for cancer treatment. The nonoxidized MXene‐Ti₃C₂T_x quantum dots (NMQDs‐Ti₃C₂T_x) are successfully prepared by a self‐designed microexplosion method. Surprisingly, it has an apparent inhibitory and killing effect on cancer cells, and excellent biocompatibility with normal cells. Moreover, the suppression rate of NMQDs‐Ti₃C₂T_x on xenograft tumor models can reach 91.9% without damaging normal tissues. Mechanistically, the Ti³⁺ of NMQDs‐Ti₃C₂T_x can react with H₂O₂ in the tumor microenvironment and high‐efficiently produce excessive toxic hydroxyl radicals to increase tumor microvascular permeability to synergistically kill cancer cells. This work should pave the way for tumor catalytic therapy applications of Ti‐based material as a promising and safer route.     

Gd43+[AlPCS4]34− Nanoagent Generating 1O2 for Photodynamic Therapy

Gd₄³⁺[AlPCS₄]₃^4? (AlPCS₄: aluminium(III) chlorido phthalocyanine tetrasulfonate) inorganic–organic hybrid nanoparticles (IOH‐NPs) are presented as a novel photosensitizer for singlet oxygen (¹O₂) generation with potential use in localized photodynamic therapy. The saline nanoparticles contain an unprecedented high phthalocyanine content of 81 wt% AlPCS₄; they show red emission (680 nm), and efficient ¹O₂ generation. In vitro studies (HepG2 and HeLa cells) demonstrate excellent uptake, low cytotoxicity, and a remarkable induced phototoxicity. Most interestingly, Gd₄³⁺[AlPCS₄]₃^4? IOH‐NPs (in suspension) significantly outperform the clinically approved H₄AlPCS₄ (in solution) in terms of photostability, reactive oxygen species generation, phototoxic effect in cells (i.e., Gd₄³⁺[AlPCS₄]₃^4?: LD₅₀ < 5 × 10^?6 m ; H₄AlPCS₄: LD₅₀ > 20 × 10^?6 m , both illuminated 10 min at 670 nm), as well as suppression of microcapillary networks and vascular cord formation. According to in vivo studies, IOH‐NP‐pretreated HeLa‐GFP cells injected into zebrafish larvae can be easily colocalized based on the red emission of the IOH‐NPs and the green emission of the tumor cells. Upon light exposure (0–20 min at 635 nm), the transgenic HeLa‐GFP cells show drastically reduced viability in vivo due to the induced phototoxicity of the Gd₄³⁺[AlPCS₄]₃^4? IOH‐NPs.     

Gadolinia-modified ceria photocatalyst for removal of lead (II) ions from aqueous solutions

Gd₂O₃-modified CeO₂ particles are prepared by a solid-state reaction method, and are used to remove Pb(II) ions from aqueous solutions by a photoelectrodeposition. The UV–photocatalytic activity for Pb(II) ion removal of the Gd₂O₃-modified CeO₂ is significantly higher than that of pure CeO₂. A solid solution Gd_0.1Ce_0.9O_1.95 phase coexisting with the CeO₂ matrix phase shows a high ability of photoelectrodeposition for the Pb(II) ions removal, compared to the two-phases mixture of Gd₂O₃–CeO₂. The high photocatalytic activity is also supported by a strong photoluminescence (PL) signal from the Gd_0.1Ce_0.9O_1.95–CeO₂. The high activity can be due to a formation of heterojunctions between p-type Gd_0.1Ce_0.9O_1.95 and n-type CeO₂, promoting transfer of photogenerated electron–hole pairs and efficiency restraining recombination of the charges.     

An O2 Self‐Supplementing and Reactive‐Oxygen‐Species‐Circulating Amplified Nanoplatform via H2O/H2O2 Splitting for Tumor Imaging and Photodynamic Therapy

Conventional photodynamic therapy (PDT) has limited applications in clinical cancer therapy due to the insufficient O₂ supply, inefficient reactive oxygen species (ROS) generation, and low penetration depth of light. In this work, a multifunctional nanoplatform, upconversion nanoparticles (UCNPs)@TiO₂@MnO₂ core/shell/sheet nanocomposites (UTMs), is designed and constructed to overcome these drawbacks by generating O₂ in situ, amplifying the content of singlet oxygen (¹O₂) and hydroxyl radical (?OH) via water‐splitting, and utilizing 980 nm near‐infrared (NIR) light to increase penetration depth. Once UTMs are accumulated at tumor site, intracellular H₂O₂ is catalyzed by MnO₂ nanosheets to generate O₂ for improving oxygen‐dependent PDT. Simultaneously, with the decomposition of MnO₂ nanosheets and 980 nm NIR irradiation, UCNPs can efficiently convert NIR to ultraviolet light to activate TiO₂ and generate toxic ROS for deep tumor therapy. In addition, UCNPs and decomposed Mn²⁺ can be used for further upconversion luminescence and magnetic resonance imaging in tumor site. Both in vitro and in vivo experiments demonstrate that this nanoplatform can significantly improve PDT efficiency with tumor imaging capability, which will find great potential in the fight against tumor.     

Dry etch selectivity of Gd2O3 to GaN and AlN

Gd₂O₃ is a promising gate dielectric for GaN, but little is known of its dry etching characteristics. We achieved Gd₂O₃ etch rates up to ～600 Å · min^?1 in high density Cl2-based discharges, with maximum selectivities of ～15 over GaN and ～4 over AlN. Pure Cl₂ discharges produced reverse selectivities for both Gd₂O₃/GaN and Gd₂O₃/AlN, with typical values between 0.1–0.4. When a rare gas additive such as Ar or Xe was added to the plasma chemistry, the nitrides etched faster than the oxide. This indicates that volatile etch products (GaCl₃, AlCl₃, N₂) form in Cl₂-based plasmas once the GaN or AlN bonds are broken by ion bombardment, but that GdCl_x species are not volatile. In conjunction with the low efficiency for Gd₂O₃ bond-breaking at low ion energies, this leads to low selectivity.