Multifunctional Upconversion Mesoporous Silica Nanostructures for Dual Modal Imaging and In Vivo Drug Delivery

Incorporating the agents for magnetic resonance imaging (MRI), optical imaging, and therapy in one nanostructured matrix to construct multifunctional nanomedical platform has attracted great attention for simultaneous diagnostic and therapeutic applications. In this work, a facile methodology is developed to construct a multifunctional anticancer drug nanocarrier by combining the special advantages of upconversion nanoparticles and mesoporous silica. β‐NaYF₄:Yb³⁺, Er³⁺@β‐NaGdF₄:Yb³⁺ is chosen as it can provide the dual modality of upconversion luminescence and MRI. Then mesoporous silica is directly coated onto the upconversion nanoparticles to form discrete, monodisperse, highly uniform, and core–shell structured nanospheres (labeled as UCNPs@mSiO₂), which are subsequently functionalized with hydrophilic polymer poly(ethylene glycol) (PEG) to improve the colloidal stability and biocompatibility. The obtained multifunctional nanocomposites can be used as an anticancer drug delivery carrier and applied for imaging. The anticancer drug doxorubicin (DOX) is absorbed into UCNPs@mSiO₂‐PEG nanospheres and released in a pH‐sensitive pattern. In vitro cell cytotoxicity tests on cancer cells verify that the DOX‐loaded UCNPs@mSiO₂‐PEG has comparable cytotoxicity with free DOX at the same concentration of DOX. In addition, the T₁‐weighted MRI that measures in aqueous solutions reveals that the contrast brightening increases with the concentration of Gd³⁺ component. Upconversion luminescence images of UCNPs@mSiO₂‐PEG uptaken by cells show green emission under 980 nm infrared laser excitation. Finally, the nanocomposites show low systematic toxicity and high in vivo antitumor therapy efficacy. These findings highlight the fascinating features of upconversion‐mesoporous nanocomposites as multimodality imaging contrast agents and nanocarrier for drug molecules.     

Manganese Dioxide Coated WS2@Fe3O4/sSiO2 Nanocomposites for pH‐Responsive MR Imaging and Oxygen‐Elevated Synergetic Therapy

Recently, the development of multifunctional theranostic nanoplatforms to realize tumor‐specific imaging and enhanced cancer therapy via responding or modulating the tumor microenvironment (TME) has attracted tremendous interests in the field of nanomedicine. Herein, tungsten disulfide (WS₂) nanoflakes with their surface adsorbed with iron oxide nanoparticles (IONPs) via self‐assembly are coated with silica and then subsequently with manganese dioxide (MnO₂), on to which polyethylene glycol (PEG) is attached. The obtained WS₂‐IO/S@MO‐PEG appears to be highly sensitive to pH, enabling tumor pH‐responsive magnetic resonance imaging with IONPs as the pH‐inert T2 contrast probe and MnO₂ as the pH‐sensitive T1 contrast probe. Meanwhile, synergistic combination tumor therapy is realized with such WS₂‐IO/S@MO‐PEG, by utilizing the strong near‐infrared light and X‐ray absorbance of WS₂ for photothermal therapy (PTT) and enhanced cancer radiotherapy (RT), respectively, as well as the ability of MnO₂ to decompose tumor endogenous H₂O₂ and relieve tumor hypoxia to further overcome hypoxia‐associated radiotherapy resistance. The combination of PTT and RT with WS₂‐IO/S@MO‐PEG results in a remarkable synergistic effect to destruct tumors. This work highlights the promise of developing multifunction nanocomposites for TME‐specific imaging and TME modulation, aiming at precision cancer synergistic treatment.     

Rattle‐Type Fe3O4@SiO2 Hollow Mesoporous Spheres as Carriers for Drug Delivery

Rattle‐type Fe₃O₄@SiO₂ hollow mesoporous spheres with different particle sizes, different mesoporous shell thicknesses, and different levels of Fe₃O₄ content are prepared by using carbon spheres as templates. The effects of particle size and concentration of Fe₃O₄@SiO₂ hollow mesoporous spheres on cell uptake and their in vitro cytotoxicity to HeLa cells are evaluated. The spheres exhibit relatively fast cell uptake. Concentrations of up to 150 µg mL^?1 show no cytotoxicity, whereas a concentration of 200 µg mL^?1 shows a small amount of cytotoxicity after 48 h of incubation. Doxorubicin hydrochloride (DOX), an anticancer drug, is loaded into the Fe₃O₄@SiO₂ hollow mesoporous spheres, and the DOX‐loaded spheres exhibit a somewhat higher cytotoxicity than free DOX. These results indicate the potential of Fe₃O₄@SiO₂ hollow mesoporous spheres for drug loading and delivery into cancer cells to induce cell death.     

Iodine‐Rich Semiconducting Polymer Nanoparticles for CT/Fluorescence Dual‐Modal Imaging‐Guided Enhanced Photodynamic Therapy

Photodynamic therapy (PDT) is a promising technique for cancer therapy, providing good therapeutic efficacy with minimized side effect. However, the lack of oxygen supply in the hypoxic tumor site obviously restricts the generation of singlet oxygen (¹O₂), thus limiting the efficacy of PDT. So far, the strategies to improve PDT efficacy usually rely on complicated nanosystems, which require sophisticated design or complex synthetic procedure. Herein, iodine‐rich semiconducting polymer nanoparticles (SPN‐I) for enhanced PDT, using iodine‐induced intermolecular heavy‐atom effect to elevate the ¹O₂ generation, are designed and prepared. The nanoparticles are composed of a near‐infrared (NIR) absorbing semiconducting polymer (PCPDTBT) serving as the photosensitizer and source of fluorescence signal, and an iodine‐grafted amphiphilic diblock copolymer (PEG‐PHEMA‐I) serving as the ¹O₂ generation enhancer and nanocarrier. Compared with SPN composed of PEG‐b‐PPG‐b‐PEG and PCPDTBT (SPN‐P), SPN‐I can enhance the ¹O₂ generation by 1.5‐fold. In addition, SPN‐I have high X‐ray attenuation coefficient because of the high density of iodine in PEG‐PHEMA‐I, providing SPN‐I the ability of use with computed tomography (CT) and fluorescence dual‐modal imaging. The study thus provides a simple nanotheranostic platform composed of two components for efficient CT/fluorescence dual‐modal imaging‐guided enhanced PDT.     

Enhanced In Vitro Biocompatibility and Water Dispersibility of Magnetite and Cobalt Ferrite Nanoparticles Employed as ROS Formation Enhancer in Radiation Cancer Therapy

Efficient magnetic reactive oxygen species (ROS) formation enhancing agents after X‐ray treatment are realized by functionalizing superparamagnetic magnetite (Fe₃O₄) and Co‐ferrite (CoFe₂O₄) nanoparticles with self‐assembled monolayers (SAMs). The Fe₃O₄ and CoFe₂O₄ nanoparticles are synthesized using Massart's coprecipitation technique. Successful surface modification with the SAM forming compounds 1‐methyl‐3‐(dodecylphosphonic acid) imidazolium bromide, or (2‐{2‐[2‐hydroxy‐ethoxy]‐ethoxy}‐ethyl phosphonic acid provides biocompatibility and long‐term stability of the Fe₃O₄ and CoFe₂O₄ nanoparticles in cell media. The SAM‐stabilized ferrite nanoparticles are characterized with dynamic light scattering, X‐ray powder diffraction, a superconducting quantum interference device, Fourier transform infrared attenuated total reflectance spectroscopy, zeta potential measurements, and thermogravimetric analysis. The impact of the SAM‐stabilized nanoparticles on the viability of the MCF‐7 cells and healthy human umbilical vein endothelial cells (HUVECs) is assessed using the neutral red assay. Under X‐ray exposure with a single dosage of 1 Gy the intracellular SAM stabilized Fe₃O₄ and CoFe₂O₄ nanoparticles are observed to increase the level of ROS in MCF‐7 breast cancer cells but not in healthy HUVECs. The drastic ROS enhancement is associated with very low dose modifying factors for a survival fraction of 50%. This significant ROS enhancement effect by SAM‐stabilized Fe₃O₄ and CoFe₂O₄ nanoparticles constitutes their excellent applicability in radiation therapy.     

Multifunctional RbxWO3 Nanorods for Simultaneous Combined Chemo‐photothermal Therapy and Photoacoustic/CT Imaging

Light‐triggered drug delivery based on near‐infrared (NIR)‐mediated photothermal nanocarriers has received tremendous attention for the construction of cooperative therapeutic systems in nanomedicine. Herein, a new paradigm of light‐responsive drug carrier that doubles as a photothermal agent is reported based on the NIR light‐absorber, Rb _x WO₃ (rubidium tungsten bronze, Rb‐TB) nanorods. With doxorubicin (DOX) payload, the DOX‐loaded Rb‐TB composite (Rb‐TB‐DOX) simultaneously provides a burst‐like drug release and intense heating effect upon 808‐nm NIR light exposure. MTT assays show the photothermally enhanced antitumor activity of Rb‐TB‐DOX to the MCF‐7 cancer cells. Most remarkably, Rb‐TB‐DOX combined with NIR irradiation also shows dramatically enhanced chemotherapeutic effect to DOX‐resistant MCF‐7 cells compared with free DOX, demonstrating the enhanced efficacy of combinational chemo‐photothermal therapy for potentially overcoming drug resistance in cancer chemotherapy. Furthermore, in vivo study of combined chemo‐photothermal therapy is also conducted and realized on pancreatic (Pance‐1) tumor‐bearing nude mice. Apart from its promise for cancer therapy, the as‐prepared Rb‐TB can also be employed as a new dual‐modal contrast agent for photoacoustic tomography and (PAT) X‐ray computed tomography (CT) imaging because of its high NIR optical absorption capability and strong X‐ray attenuation ability, respectively. The results presented in the current study suggest promise of the multifunctional Rb _x WO₃ nanorods for applications in cancer theranostics.     

Synthesis of BSA‐Coated BiOI@Bi2S3 Semiconductor Heterojunction Nanoparticles and Their Applications for Radio/Photodynamic/Photothermal Synergistic Therapy of Tumor

Developing an effective theranostic nanoplatform remains a great challenge for cancer diagnosis and treatment. Here, BiOI@Bi₂S₃@BSA (bovine serum albumin) semiconductor heterojunction nanoparticles (SHNPs) for triple‐combination radio/photodynamic/photothermal cancer therapy and multimodal computed tomography/photoacoustic (CT/PA) bioimaging are reported. On the one hand, SHNPs possess strong X‐ray attenuation capability since they contain high‐Z elements, and thus they are anticipated to be a very competent candidate as radio‐sensitizing materials for radiotherapy enhancement. On the other hand, as a semiconductor, the as‐prepared SHNPs offer an extra approach for reactive oxygen species generation based on electron–hole pair under the irradiation of X‐ray through the photodynamic therapy process. This X‐ray excited photodynamic therapy obviously has better penetration depth in bio‐tissue. What's more, the SHNPs also possess well photothermal conversion efficiency for photothermal therapy, because Bi₂S₃ is a thin band semiconductor with strong near‐infrared absorption that can cause local overheat. In vivo tumor ablation studies show that synergistic radio/photodynamic/photothermal therapy achieves more significant therapeutic effect than any single treatment. In addition, with the strong X‐ray attenuation and high near‐infrared absorption, the as‐obtained SHNPs can also be applied as a multimodal contrast agent in CT/PA imaging.     

TPGS‐Functionalized Polydopamine‐Modified Mesoporous Silica as Drug Nanocarriers for Enhanced Lung Cancer Chemotherapy against Multidrug Resistance

A nanocarrier system of d ‐a‐tocopheryl polyethylene glycol 1000 succinate (TPGS)‐functionalized polydopamine‐coated mesoporous silica nanoparticles (NPs) is developed for sustainable and pH‐responsive delivery of doxorubicin (DOX) as a model drug for the treatment of drug‐resistant nonsmall cell lung cancer. Such nanoparticles are of desired particle size, drug loading, and drug release profile. The surface morphology, surface charge, and surface chemical properties are also successfully characterized by a series of techniques such as transmission electron microscopy (TEM), X‐ray photoelectron spectroscopy (XPS), Brunauer‐Emmett‐Teller (BET) method, thermal gravimetric analysis (TGA), dynamic light scattering (DLS), and Fourier transform infrared spectroscopy (FTIR). The normal A549 cells and drug‐resistant A549 cells are employed to access the cytotoxicity and cellular uptake of the NPs. The therapeutic effects of TPGS‐conjugated nanoparticles are evaluated in vitro and in vivo. Compared with free DOX and DOX‐loaded NPs without TPGS ligand modification, MSNs‐DOX@PDA‐TPGS exhibits outstanding capacity to overcome multidrug resistance and shows better in vivo therapeutic efficacy. This splendid drug delivery platform can also be sued to deliver other hydrophilic and hydrophobic drugs.     

Safe and Effective Reversal of Cancer Multidrug Resistance Using Sericin‐Coated Mesoporous Silica Nanoparticles for Lysosome‐Targeting Delivery in Mice

Multidrug resistance (MDR) and adverse side effects are the major challenges facing cancer chemotherapy. Here, pH/protease dually responsive, sericin‐coated mesoporous silica nanoparticles (SMSNs) for lysosomal delivery of doxorubicin (DOX) to overcome MDR and reduce systemic toxicity are reported. Sericin, a natural protein from silkworm cocoons, is coated onto MSNs as a gatekeeper via pH sensitive imine linkages. The sericin shell prevents the premature leakage of encapsulated DOX from MSNs in extracellular environment. Once reaching drug‐resistant tumors, sericin's cell‐adhesive bioactivity enhances cellular uptake of SMSNs that are in turn transported into perinuclear lysosomes, thus avoiding drug efflux mediated by membrane‐bound pumps. Lysosomal acidity triggers cleavage of pH sensitive linkage between sericin and MSNs concurrently with lysosomal proteases deconstructing sericin shell. This pH/protease dual responsiveness leads to DOX burst release into cell nuclei, inducing effective cell death, thus reversing MDR. These DOX‐loaded SMSNs not only effectively kill drug‐resistant cells in vitro, but also significantly reduce the growth of DOX‐resistant MCF‐7/ADR (breast cancer cells) tumor by 70% in a preclinical animal model without eliciting systemic toxicity frequently encountered in current clinical therapeutic formulations. Thus, the dually responsive SMSNs are an effective, lysosome‐tropic, and bio‐safe delivery system for chemotherapeutics for combating MDR.     

Mesoporous silica-coated gold nanorods with a thermally responsive polymeric cap for near-infrared-activated drug delivery

In this work, gold nanorods (AuNRs)/mesoporous silica (SiO₂) nanoparticles capped with thermal-responsive polymer were fabricated to couple the photothermal property of AuNRs and the thermal-/pH-responsive properties of polymer in a single nanovehicle. Aliphatic poly(urethane-amine) (PUA) was employed as the smart polymer to cap the mesopores of AuNRs/SiO₂ nanoparticles via in situ polymerization in supercritical CO₂. Thermal-/pH-responsive PUA acted as the on–off switch to control the DOX release due to the stretch and shrinkage of the PUA polymer chains at different temperatures, whereas a remote near-infrared (NIR) light was used to activate the phase change and subsequent drug release. The in vitro drug release studies indicated that Au/SiO₂/PUA nanoparticles exhibited distinguished pH-, thermal-, and NIR-dependent release properties. A short time exposure to NIR irradiation could distinctly increase the local temperature of nanoparticles, and the thermal-responsive polymeric cap enabled the DOX release in a significant reversible way by simply adjusting the NIR laser intensity. The present paper provides an ideal way to fabricate NIR-responsive drug carriers by combining stimuli-responsive polymer with inorganic matrix, which is highly attractive for remote controllable drug delivery.     

ZIF‐67‐Derived 3D Hollow Mesoporous Crystalline Co3O4 Wrapped by 2D g‐C3N4 Nanosheets for Photocatalytic Removal of Nitric Oxide

ZIF‐67‐derived 3D hollow mesoporous crystalline Co₃O₄ wrapped by 2D graphitic carbon nitride (g‐C₃N₄) nanosheets are prepared by low temperature annealing, and are used for the photocatalytic oxidation of nitric oxide (NO) at a concentration of 600 ppb. The p–n heterojunction between Co₃O₄ and g‐C₃N₄ forms a spatial conductive network frame and results in a broad visible light response range. The hollow mesoporous structure of Co₃O₄ contributes to the circulation and adsorption of NO, and the large specific surface area exposes abundant active sites for the reaction of active species. A maximum NO degradation efficiency of 57% is achieved by adjusting the mass of the Co₃O₄ precursor. Cycling tests and X‐ray diffraction indicate the high stability and recyclability of the composite, making it promising in environmental purification applications.     

Gold Nanorods Coated with Mesoporous Silica Shell as Drug Delivery System for Remote Near Infrared Light‐Activated Release and Potential Phototherapy

In this study, we report the synthesis of a nanoscaled drug delivery system, which is composed of a gold nanorod‐like core and a mesoporous silica shell (GNR@MSNP) and partially uploaded with phase‐changing molecules (1‐tetradecanol, TD, T_m 39 °C) as gatekeepers, as well as its ability to regulate the release of doxorubicin (DOX). Indeed, a nearly zero premature release is evidenced at physiological temperature (37 °C), whereas the DOX release is efficiently achieved at higher temperature not only upon external heating, but also via internal heating generated by the GNR core under near infrared irradiation. When tagged with folate moieties, GNR@MSNPs target specifically to KB cells, which are known to overexpress the folate receptors. Such a precise control over drug release, combining with the photothermal effect of GNR cores, provides promising opportunity for localized synergistic photothermal ablation and chemotherapy. Moreover, the performance in killing the targeted cancer cells is more efficient compared with the single phototherapeutic modality of GNR@MSNPs. This versatile combination of local heating, phototherapeutics, chemotherapeutics and gating components opens up the possibilities for designing multifunctional drug delivery systems.     

Nanoparticles of Mesoporous SO3H‐Functionalized Si‐MCM‐41 with Superior Proton Conductivity

Nanometer‐sized mesoporous silica particles of around 100‐nm diameter functionalized with a large amount of sulfonic acid groups are prepared using a simple and fast in situ co‐condensation procedure. A highly ordered hexagonal pore structure is established by applying a pre‐hydrolysis step in a high‐dilution synthesis approach, followed by adding the functionalization agent to the reaction mixture. The high‐dilution approach is advantageous for the in situ functionalization since no secondary reagents for an effective particle and framework formation are needed. Structural data are determined via electron microscopy, nitrogen adsorption, and X‐ray diffraction, proton conductivity values of the functionalized samples are measured via impedance spectroscopy. The obtained mesoporous SO₃H‐MCM‐41 nanoparticles demonstrate superior proton conductivity than their equally loaded micrometer‐sized counterparts, up to 5 × 10^?2 S cm^?1. The mesoporosity of the particles turns out to be very important for effective proton transport since non‐porous silica nanoparticles exhibit worse efficient proton transport, and the obtained particle size dependence might open up a new route in rational design of highly proton conductive materials.     

Anti‐Biofouling Polymer‐Decorated Lutetium‐Based Nanoparticulate Contrast Agents for In Vivo High‐Resolution Trimodal Imaging

Nanomaterials have gained considerable attention and interest in the development of novel and high‐resolution contrast agents for medical diagnosis and prognosis in clinic. A classical urea‐based homogeneous precipitation route that combines the merits of in situ thermal decomposition and surface modification is introduced to construct polyethylene glycol molecule (PEG)‐decorated hybrid lutetium oxide nanoparticles (PEG–UCNPs). By utilizing the admirable optical and magnetic properties of the yielded PEG–UCNPs, in vivo up‐conversion luminescence and T₁‐enhanced magnetic resonance imaging of small animals are conducted, revealing obvious signals after subcutaneous and intravenous injection, respectively. Due to the strong X‐ray absorption and high atomic number of lanthanide elements, X‐ray computed‐tomography imaging based on PEG–UCNPs is then designed and carried out, achieving excellent imaging outcome in animal experiments. This is the first example of the usage of hybrid lutetium oxide nanoparticles as effective nanoprobes. Furthermore, biodistribution, clearance route, as well as long‐term toxicity are investigated in detail after intravenous injection in a murine model, indicating the overall safety of PEG–UCNPs. Compared with previous lanthanide fluorides, our nanoprobes exhibit more advantages, such as facile construction process and nearly total excretion from the animal body within a month. Taken together, these results promise the use of PEG–UCNPs as a safe and efficient nanoparticulate contrast agent for potential application in multimodal imaging.     

Redox/pH dual stimuli‐responsive ZnO QDs‐gated mesoporous silica nanoparticles as carriers in cancer therapy

New drug delivery system (ZnO@CMS) of the redox and pH dual‐stimuli responsive based on colloidal mesoporous silica nanoparticles (CMS) has been designed, in which zinc oxide quantum dots (ZnO QDs) as a capping agent was conjugated on the surface of nanoparticles by amide bonds. The release behaviour of doxorubicin (DOX) as the model drug from ZnO@CMS (ZnO@CMS‐DOX) indicated the redox and pH dual‐stimuli responsive properties due to the acidic dissolution of ZnO QDs and cleavage of the disulphide bonds. The haemolysis and bovine serum albumin adsorption assays showed that the modification of ZnO QDs on the mesoporous silica nanoparticles modified by mercapto groups (CMS‐SH)(ZnO@CMS) had better biocompatibility compared to CMS‐SH. The cell viability and cellular uptake tests revealed that the ZnO@CMS might achieve the antitumour effect on cancer cells due to the cytotoxicity of ZnO QDs. Therefore, ZnO@CMS might be potential nanocarriers of the drug delivery system in cancer therapy. The in vivo evaluation of ZnO@CMS would be carried out in future work.Inspec keywords: biochemistry, nanomedicine, cellular biophysics, pH, toxicology, tumours, semiconductor quantum dots, proteins, colloids, II‐VI semiconductors, mesoporous materials, silicon compounds, oxidation, cancer, drug delivery systems, zinc compounds, adsorption, molecular biophysics, nanomagnetics, drugs, biomedical materials, nanofabrication, nanoparticles, nanoporous materialsOther keywords: cancer therapy, drug delivery system, amide bonds, haemolysis, bovine serum albumin adsorption assays, mercapto groups, cancer cells, cytotoxicity, antitumour effect, redox/pH dual stimuli‐responsive zinc oxide quantum dots‐gated colloidal mesoporous silica nanoparticles, ZnO, SiO₂      

Revealing Nanoscale Chemical Heterogeneities in Polycrystalline Mo‐BiVO4 Thin Films

The activity of polycrystalline thin film photoelectrodes is impacted by local variations of the material properties due to the exposure of different crystal facets and the presence of grain/domain boundaries. Here a multi‐modal approach is applied to correlate nanoscale heterogeneities in chemical composition and electronic structure with nanoscale morphology in polycrystalline Mo‐BiVO₄. By using scanning transmission X‐ray microscopy, the characteristic structure of polycrystalline film is used to disentangle the different X‐ray absorption spectra corresponding to grain centers and grain boundaries. Comparing both spectra reveals phase segregation of V₂O₅ at grain boundaries of Mo‐BiVO₄ thin films, which is further supported by X‐ray photoelectron spectroscopy and many‐body density functional theory calculations. Theoretical calculations also enable to predict the X‐ray absorption spectral fingerprint of polarons in Mo‐BiVO₄. After photo‐electrochemical operation, the degraded Mo‐BiVO₄ films show similar grain center and grain boundary spectra indicating V₂O₅ dissolution in the course of the reaction. Overall, these findings provide valuable insights into the degradation mechanism and the impact of material heterogeneities on the material performance and stability of polycrystalline photoelectrodes.     

Toxic Reactive Oxygen Species Enhanced Synergistic Combination Therapy by Self‐Assembled Metal‐Phenolic Network Nanoparticles

Engineering functional nanomaterials with high therapeutic efficacy and minimum side effects has increasingly become a promising strategy for cancer treatment. Herein, a reactive oxygen species (ROS) enhanced combination chemotherapy platform is designed via a biocompatible metal‐polyphenol networks self‐assembly process by encapsulating doxorubicin (DOX) and platinum prodrugs in nanoparticles. Both DOX and platinum drugs can activate nicotinamide adenine dinucleotide phosphate oxidases, generating superoxide radicals (O₂^??). The superoxide dismutase‐like activity of polyphenols can catalyze H₂O₂ generation from O₂^??. Finally, the highly toxic HO^? free radicals are generated by a Fenton reaction. The ROS HO^? can synergize the chemotherapy by a cascade of bioreactions. Positron emission tomography imaging of ⁸⁹Zr‐labeled as‐prepared DOX@Pt prodrug Fe³⁺ nanoparticles (DPPF NPs) shows prolonged blood circulation and high tumor accumulation. Furthermore, the DPPF NPs can effectively inhibit tumor growth and reduce the side effects of anticancer drugs. This study establishes a novel ROS promoted synergistic nanomedicine platform for cancer therapy.     

Magnetic properties of SBA-15 mesoporous nanocomposites with CoFe2O4 nanoparticles

A novel mesoporous nanocomposite based on SBA-15 with CoFe₂O₄ and Fe₂O₃ magnetic nanoparticles was prepared via the hydrothermal treatment and impregnation method. We showed that Fe₂O₃ nanoparticles were anchored in the frame and CoFe₂O₄ nanoparticles were confined in the mesopores of SBA-15 in the prepared nanocomposite. Our results indicated that the magnetic properties could be adjusted by the addition of CoFe₂O₄ and Fe₂O₃ magnetic nanoparticles. The presence of couple exchange interaction was confirmed with Kelly-Hankel (δM) curves, which enhanced the magnetic properties of the CoFe₂O₄/Fe₂O₃-SBA-15 mesoporous nanocomposite.     

Hollow iron oxide nanoparticles as multidrug resistant drug delivery and imaging vehicles

Magnetic nanoparticles have been used as drug delivery vehicles against a number of cancer cells. Most of these theranostic formulations have used solid iron oxide nanoparticles (SIONPs) loaded with chemotherapeutics as nano-carrier formulation for both magnetic resonance imaging (MRI) and cancer therapy. In this study, we applied the dopamine-plus-human serum albumin (HSA) method to modify hollow iron oxide nanoparticles (HIONPs) and encapsuated doxorubicin (DOX) within the hollow porous structure of the nano-carrier. The new delivery system can load more drug than solid iron oxide nanoparticles of the same core size using the same coating strategy. The HIONPs-DOX formulation also has a pH-dependent drug release behaviour. Compared with free DOX, the HIONPs-DOX were more effectively uptaken by the multidrug resistant OVCAR8-ADR cells and consequently more potent in killing drug resistant cancer cells. MRI phantom and cell studies also showed that the HIONPs-DOX can decrease the T ₂ MRI signal intensity and can be used as a MRI contrast agent while acting as a drug delivery vehicle. For the first time, the dual application of chemo drug transport and MR imaging using the HIONPs-DOX formulation was achieved against both DOX-sensitive and DOX-resistant cancer cells.      

Synthesis of mesoporous β-Ga2O3 nanorods using PEG as template: Preparation, characterization and photocatalytic properties

Mesoporous wide bandgap semiconductors offer high photocatalytic oxidation and mineralization activities. In this study, mesoporous β-Ga₂O₃ diamond nanorods with 200-300 nm in diameter and 1.0-1.2 μm in length were synthesized via a urea-based hydrothermal method using polyethylene glycol (PEG) as template agent. The UV photocatalytic oxidation activity of β-Ga₂O₃ for gaseous toluene was evaluated, and 7 kinds of intermediates were monitored online by a proton transfer reaction mass spectrometry. Photoluminescence spectra manifested that the dosage and molecular weight of PEG are crucial for formation of vacancies and photocatalytic oxidation activities. A PEG-assisted hydrothermal formation mechanism of mesoporous β-Ga₂O₃ diamond nanorods was proposed. Based on the health risk influence index (η) of the intermediates, the calculated health risks revealed that the β-Ga₂O₃ nanorods with a η value of 9.6 are much safer than TiO₂ (η = 17.6).