Wuli Yang

Targeting mesoporous silica-encapsulated gold nanorods for chemo-photothermal therapy with near-infrared radiation

Mesoporous silica-encapsulated gold nanorods (GNRs@mSiO(2)) have great potential both in photothermal therapy and drug delivery. In this paper, we firstly developed GNRs@mSiO(2) as a synergistic therapy tool for delivery heat and drug to the tumorigenic region. We studied the ablation of tumor both in vitro and in vivo by the combination of photothermal therapy and chemotherapy using doxorubicin (DOX)-loaded GNRs@mSiO(2). Significantly greater cell killing was observed when A549 cells incubated with DOX-loaded GNRs@mSiO(2) were irradiated with near-infrared (NIR) illumination, attributable to both GNRs@mSiO(2)-mediated photothermal ablation and cytotoxicity of light-triggered DOX release. We then performed in vivo therapy studies and observed a promising tumor treatment. Compared with chemotherapy or photothermal treatment alone, the combined treatment showed a synergistic effect, resulting in higher therapeutic efficacy. Furthermore, the lower systematic toxicity of GNRs@mSiO(2) has been validated.

Realizing Ultrahigh Modulus and High Strength of Macroscopic Graphene Oxide Papers Through Crosslinking of Mussel-Inspired Polymers

Covalently crosslinked graphene oxide papers (GOPs) with enhanced mechanical properties are prepared by a strategy involving crosslinking by means of intercalated polymers. The strength and modulus of the crosslinked GOPs increase by 115% and 550%, respectively, compared to the pristine GOPs. These results broaden the potential applications of graphene, and the crosslinking strategy will open the door to the assembly of other nanometer-scale materials.

Thermo and pH dual responsive, polymer shell coated, magnetic mesoporous silica nanoparticles for controlled drug release

In this paper, a kind of core–shell composite microsphere was prepared based on poly(N-isopropylacrylamide-co-methacrylic acid) (P(NIPAM-co-MAA)) coated magnetic mesoporous silica nanoparticles (M-MSN) via precipitation polymerization. The composite microsphere presented a thermo/pH-coupling sensitivity and the volume phase transition could be precisely regulated by the molar ratio of MAA to NIPAM or the concentration of NaCl. At physiological conditions (37 °C, 0.15 M NaCl), the P(NIPAM-co-MAA) shell underwent a distinct transition from a swollen state in pH 7.4 to a collapsed state in pH 5.0, so that the polymer shell was active in moderating the diffusion of embedded drugs in-and-out of the pore channels of MSN. Doxorubicin hydrochloride (DOX) was applied as a model drug and the behaviors of drug storage/release were investigated. The drug loaded behavior was pH-dependent, and the composite microsphere had a drug embed efficiency of about 91.3% under alkaline conditions. The cumulative in vitro release of the DOX-loaded composite microsphere showed a low level of leakage below the volume phase transition temperature (VPTT) and was significantly enhanced above its VPTT, exhibiting an apparent thermo/pH-response controlled drug release. The cytotoxicity assay of a blank carrier to normal cells indicated that the composite microspheres were suitable as drug carriers, while the DOX-loaded composite microspheres had a similar cytotoxicity to HeLa cells compared with free DOX. Therefore, the thermo/pH-sensitive composite microsphere could, in principle, be used for in vivo cancer therapy with a low premature drug release during blood circulation whilst having a rapid release upon reaching tumor tissues.

Multi-Functional Thermosensitive Composite Microspheres with High Magnetic Susceptibility Based on Magnetite Colloidal Nanoparticle Clusters

Monodisperse organic/inorganic composite microspheres with well-defined structure were prepared through the encapsulation of silica coated superparamagnetic magnetite colloidal nanoparticle clusters (CNCs) with cross-linked poly(N-isopropylacrylamide) (PNIPAM) shell. At first, the sub-micrometer-sized CNCs were fabricated by the solvothermal process, and then a silica layer was coated on the surface of CNCs through a sol-gel process, and finally, a thermoresponsive shell of PNIPAM was deposited onto the surface of the core/shell magnetic microspheres by a precipitation polymerization. The experimental results showed that the size of Fe(3)O(4) core, the thickness of SiO(2) shell, as well as volume phase transition temperature (VPTT) of PNIPAM shell could be well controlled, and this structured modulation could satisfy different requirements. The superparamagnetic behavior, high magnetization (the saturation magnetization of Fe(3)O(4)/SiO(2)/PNIPAM microspheres with a 10% cross-linking density is 41.6 emu/g), and good thermosensitivity make these composite microspheres an ideal candidate for various important applications such as in controlled drug delivery, bioseparation, and catalysis.

Magnetic mesoporous silica microspheres with thermo-sensitive polymer shell for controlled drug release

A controlled drug release system was designed based on the combination of three advantages into one entity, which was composed of Fe3O4 magnetic nanoparticle as the core, mesoporous silica as the sandwiched layer, and thermo-sensitive P(NIPAM-co-NHMA) copolymer as the outer shell. The hydrophilic comonomer content affected the volume phase-transition temperature (VPTT) of this composite microsphere and the behavior of the temperature-triggered drug release. Zn(II) phthalocyanine tetrasulfonic acid (ZnPcS4), a well-known photodynamic therapy (PDT) drug, was used as a model drug to assess the release system. The results demonstrated that the drug release behavior was dependent on the temperature and had a close correlation with the VPTT. Above the VPTT, the drug release rate was much faster than that below the VPTT, which showed a great potential application in tumor therapy.

Facile synthesis of pH sensitive polymer-coated mesoporous silica nanoparticles and their application in drug delivery

pH-responsive polymer shell chitosan/poly (methacrylic acid) (CS-PMAA) was coated on mesoporous silica nanoparticles (MSN) through the facile in situ polymerization method. The resultant composite microspheres showed a flexible control over shell thickness, surface charges and hydrodynamic size by adjusting the feeding amount of MSN and the molar ratio of [-NH(2)]/MAA. The MSN/CS-PMAA composite microspheres were stable in the pH range of 5-8 as well as in the physiological saline (0.15M NaCl). Doxorubicin hydrochloride (DOX) was applied as a model drug to investigate the drug storage and release behavior. The results demonstrated that DOX could be effectively loaded into the composite microspheres. The cumulative release of DOX-loaded composite microspheres was pH dependent and the release rate was much faster at low pH (5.5) than that of pH 7.4. The cytotoxicity test by MTT assay showed that the blank carrier MSN/CS-PMAA microspheres were suitable as drug carriers. The cellular uptake of composite microspheres was investigated by confocal laser scanning microscopy (CLSM), which indicated that MSN/CS-PMAA could deliver the drugs into HeLa cell. The above results imply that the composite microspheres are a promising drug delivery system for cancer therapy.

Magnetic Colloidal Supraparticles: Design, Fabrication and Biomedical Applications†

Magnetic nanoparticles (MNPs) bear many intriguing properties such as superparamagnetism, high specific surface area, remarkable colloidal stability and biocompatibility, which evoke great interest and desire of exploration in biomedical applications. For the use in the complicated physiological environment, MNPs are still being developed to have the enhanced performances and down-to-earth practicality. Engineering of MNPs into hierarchical structures is thus proposed to create a new family of magnetic materials, magnetic colloidal supraparticles (MCSPs), which exhibit collective properties and unique nanomaterial characters. From a biomedical point of view, applicability of MCSPs is somewhat more distinctive in contrast to their primary MNPs, because MCSPs are amenable to modulation of secondary structure, promotion of magnetic responsiveness and ease of function design. As a result, MCSPs have been subject to intense researches in recent years, with the aim to develop outstanding composite materials for biomedical applications. In this review, we embark on an overview of foundational topics that detail the design and fabrication of MCSPs by evaporation-induced emulsion and solvothermal techniques, and continue with a guideline for modification of MCSPs with inorganic oxides and organic polymers. Particular focus is then placed on the biomedical applications of modified MCSPs. Many examples illustrate the latest progress in design of MCSP-based microspheres for magnetic resonance imaging, targeted drug delivery, sensing, and harvesting of peptides/proteins. After these detailed accounts, the current challenges and future development of researches and applications are discussed as a conclusion to the review.

Poly(vinylcaprolactam)-based biodegradable multiresponsive microgels for drug delivery.

Poly(vinylcaprolactam) (PVCL)-based biodegradable microgels were prepared for the biomedical application as drug delivery system via precipitation polymerization, where N,N-bis(acryloyl) cystamine (BAC) served as cross-linker, methacrylic acid (MAA) and polyethylene glycol (PEG) methyl ether methacrylate acted as comonomers. The microgels with excellent stability had distinct temperature sensitivity as largely observed in the case of PVCL-based particles and their volume phase transition temperature (VPTT) shifted to higher temperature with increasing MAA content and ambient pH. In the presence of reducing agent glutathione (GSH) or dithiothreitol (DTT), the microgels could be degraded into individual linear polymer chains by the cleavage of the disulfide linkages coming from the cross-linker BAC. The microgels could effectively encapsulate Doxorubicin (DOX) inside and presented stimuli-triggered drug release in acidic or reducing environment. The results of the cytotoxicity assays further demonstrated that the blank microgels were nontoxic to normal cells while DOX-loaded microgels presented efficient antitumor activity to HeLa cells.

Doxorubicin‐Loaded Magnetic Silk Fibroin Nanoparticles for Targeted Therapy of Multidrug‐Resistant Cancer

A strategy to prepare doxorubicin-loaded magnetic silk fibroin nanoparticles is presented. The nanoparticles serve as a nanometer-scale drug-delivery system in the chemotherapy of multidrug-resistant cancer under the guidance of a magnetic field. The magnetic tumor-targeting ability broadens the range of biomedical applications of silk fibroin, and the nanoparticle-assisted preparation strategy is useful for the advancement of other biomacromolecule-based materials.

Synthesis of high-quality near-infrared-emitting CdTeS alloyed quantum dots via the hydrothermal method

We present a facile one-pot method to fabricate water-dispersed near-infrared-emitting (650?800?nm) CdTeS alloyed quantum dots with high photoluminescence quantum yields (PL QYs). Due to the hydrolysis of thiol ligands, the sulfur was incorporated into the CdTe nanocrystals, forming CdTeS alloyed QDs. The effects of the type of thiol ligands, ligand-to-Cd molar ratio, and precursor concentration on the QDs were investigated, and thus high-quality water-dispersed CdTeS alloyed QDs (PL QYs 68%) were prepared with a high efficiency via the hydrothermal method. Water-dispersed CdTeS alloyed QDs with excellent emissions in the near-IR spectrum window have great potential in biological and medical applications especially in in?vivo imaging.