The bromoporphyrins as promising anti-tumor photosensitizers in vitro.

The synthesis of ideal photosensitizers (PSs) is considered to be the most significant bottleneck in photodynamic therapy (PDT). To discover novel PSs with excellent photodynamic anti-tumor activities, a series of novel photosensitizers 5,15-diaryl-10,20-dibromoporphyrins (I1-6) were synthesized by a facile method. Compared with hematoporphyrin monomethyl ether (HMME) as the representative porphyrin-based photosensitizers, it is found that not only the longest absorption wavelength of all compounds was red-shifted to therapeutic window (660 nm) of photodynamic therapy, but also the singlet oxygen quantum yields were significantly increased. Furthermore, all compounds exhibited lower dark toxicity (except I2) and stronger phototoxicity (except I4) against Eca-109 tumor cells than HMME. Among them, I3 possessed the highest singlet oxygen quantum yield (ΦΔ = 0.205), the lower dark toxicity and the strongest phototoxicity (IC50 = 3.5 µM) in vitro. The findings indicated the compounds I3 had the potential to become anti-tumor agents for PDT.

Synthesis and evaluation of novel fluorinated hematoporphyrin ether derivatives for photodynamic therapy.

A photosensitizer with high phototoxicity, suitable amphipathy and low dark toxicity could play a pivotal role in photodynamic therapy (PDT). In this study, a facile and versatile approach was adopted to synthesize a series of novel fluorinated hematoporphyrin ether derivatives (I1-I5 and II1-II4), and the photodynamic activities of these compounds were studied. Compared to hematoporphyrin monomethyl ether (HMME), all PSs showed preferable photodynamic activity against A549 lung tumor cells. The longest visible absorption wavelength of these compounds was approximately 622 nm. Among them, II3 revealed the highest singlet oxygen yield (0.0957 min-1), the strongest phototoxicity (IC50 = 1.24 µM), the lowest dark toxicity in vitro, and exhibited excellent anti-tumor effects in vivo. So compound II3 could act as new drug candidate for photodynamic therapy.

Self-Assembled Binary Photonic Crystals under the Active Confinement and Their Light Trapping.

The self-assembly of oppositely charged colloidal ellipsoids and spheres under active confinement is first proposed to achieve long-range ordered photonic crystals. Compared with the conventional passive confinement, a characteristic of the active confinement is that boundaries are movable. Our Brownian dynamics simulations show that dynamic steady structures, similar to quasi-2D colloidal crystals, can be obtained under the strong confinement when the two boundaries periodically oscillate together. The in-plane structures can be regulated by changing the charge ratio of the two kinds of particles. These dynamic steady structures are determined by the minimum electrostatic energy with the aid of increased mobility of confined particles, which are not available in equilibrium. Numerical simulations verify that light can be perfectly confined in this dielectric binary photonic slab without any radiation, which corresponds to a typical optical bound state with divergent lifetime and ultrasharp spectral profile. Given the changeable geometry of this photonic slab, the trapped optical field might be applicable to enhanced light-matter interactions. In addition, for thicker layers, layer-by-layer ordered structures occur spontaneously, driven by the active confinement, while no global order occurs in the passive confinement. Our results show that the boundary motion can become an important factor affecting self-assembled structure and function.

Water-soluble graphene grafted by poly(sodium 4-styrenesulfonate) for enhancement of electric capacitance.

Water-soluble poly(sodium 4-styrenesulfonate) modified graphene (PSSS-GR) was successfully synthesized via covalently grafting poly(sodium 4-styrenesulfonate) (PSSS) on the surfaces of graphene (GR) nanosheets. The structure of PSSS-GR was investigated with Fourier transform infrared, x-ray photoelectron and Raman spectroscopy, thermogravimetric analysis, transmission and scanning electron microscopy and atomic force microscopy. The PSSS chains made the GR nanosheets fully exfoliate into a single-layer structure, and the PSSS layer on GR reached 90 wt%. PSSS chains displayed mutually repulsive effects on promoting GR sheets that were more stable in water. The performances of supercapacitors made of PSSS-GR and unmodified GR electrodes were compared using cyclic voltammetry and galvanostatic charge/discharge techniques. The results showed that PSSS is an effective binder for graphene sheets and can increase the specific capacitance of PSSS-GR based supercapacitors and improve their rate capability. The maximum specific capacitance of the PSSS-GR based supercapacitor was 210 F g(-1) at 5 A g(-1), which was 166% higher than for one made of unmodified graphene electrodes. Electrochemical impedance spectroscopy demonstrated fast ion diffusion in the PSSS-GR electrode structure. PSSS-GR based supercapacitors can fulfil one of the essential requirements for potential electric energy storage applications.

The Photodynamic Anti-Tumor Effects of New PPa-CDs Conjugate with pH Sensitivity and Improved Biocompatibility.

BACKGROUND: Photodynamic therapy has been increasingly used to cope with the alarming problem of cancer. Porphyrins and their derivatives are widely used as Potent Photosensitizers (PS) for PDT. However, the hydrophobicity of porphyrins poses a challenge for their use in clinics, while most of the carbon dots (CDs) are known for good biocompatibility, solubility, and pH sensitivity. OBJECTIVE: This study aimed to improve the properties/biocompatibility of the pyropheophorbide-α for PDT. METHODS: The PPa-CD conjugate was synthesized through covalent interaction using amide condensation. The structure of synthesized conjugate was confirmed by TEM, 1HNMR, and FTIR. The absorption and emission spectra were studied. In vitro, cytotoxicity of the conjugate was examined in human esophageal cancer cell line (Eca-109). RESULTS: The results showed that the fluorescence of the drug was increased compared to its precursor. CDbased conjugate could generate ROS as well as enhanced biocompatibility by decreasing cytotoxicity. The conjugated drug also showed pH sensitivity in different solutions. CONCLUSION: The dark toxicity, as well as hemocompatibility, was improved.

A simple and controllable graphene-templated approach to synthesise 2D silica-based nanomaterials using water-in-oil microemulsions.

Using the versatility of silica chemistry, we describe herein a simple and controllable approach to synthesise two-dimensional (2D) silica-based nanomaterials: the diversity and utility of the resulting structures offer excellent platforms for many potential applications.

Silica hybrid particles with nanometre polymer shells and their influence on the toughening of polypropylene.

Colloidal silica particles were synthesized by the sol-gel process and then modified with 3-methacryloxypropyltrimethoxysilane (γ-MPS) to induce vinyl groups on the surface of the silica particles. By means of in situ emulsion copolymerization of methyl methacrylate (MMA) and butyl acrylate (BA), a series of core-shell silica hybrid particles with nanometre poly(MMA-co-BA) shells were fabricated, which were subsequently compounded with isotactic polypropylene (PP) in the molten state. Upon increasing the feed silica : monomer ratio from 1 : 1 to 4 : 1, the poly(MMA-co-BA) shell thickness on the silica core decreased from 50 nm to 10 nm. Owing to the existence of the nanometre poly(MMA-co-BA) shells, the silica hybrid particles were monodispersed in the PP matrix, causing homogeneous debonding at the PP/silica interface, followed by plastic void expansion and matrix shear yielding during impact fracture. These deformation mechanisms greatly toughened the PP-silica composites. A critical shell thickness of poly(MMA-co-BA) was needed to achieve optimal mechanical properties. That is, when the polymer shell thickness was 15 nm, compared to pure PP, the impact toughness of the PP-silica composite was more than doubled with little degradation of tensile strength.

Studies on Preparation of Photosensitizer Loaded Magnetic Silica Nanoparticles and Their Anti-Tumor Effects for Targeting Photodynamic Therapy.

As a fast developing alternative of traditional therapeutics, photodynamic therapy (PDT) is an effective, noninvasive, nontoxic therapeutics for cancer, senile macular degeneration, and so on. But the efficacy of PDT was compromised by insufficient selectivity and low solubility. In this study, novel multifunctional silica-based magnetic nanoparticles (SMNPs) were strategically designed and prepared as targeting drug delivery system to achieve higher specificity and better solubility. 2,7,12,18-Tetramethyl-3,8-di-(1-propoxyethyl)-13,17-bis-(3-hydroxypropyl) porphyrin, shorted as PHPP, was used as photosensitizer, which was first synthesized by our lab with good PDT effects. Magnetite nanoparticles (Fe(3)O(4)) and PHPP were incorporated into silica nanoparticles by microemulsion and sol-gel methods. The prepared nanoparticles were characterized by transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and fluorescence spectroscopy. The nanoparticles were approximately spherical with 20-30 nm diameter. Intense fluorescence of PHPP was monitored in the cytoplasm of SW480 cells. The nanoparticles possessed good biocompatibility and could generate singlet oxygen to cause remarkable photodynamic anti-tumor effects. These suggested that PHPP-SMNPs had great potential as effective drug delivery system in targeting photodynamic therapy, diagnostic magnetic resonance imaging and magnetic hyperthermia therapy. GRAPHICAL ABSTRACT: Novel multifunctional photosensitizer loaded magnetic silica nanoparticles were strategically prepared with low toxicity, good biocompatibility and remarkable photodynamic anti-tumor efficacy. The nanoparticles were believed to be of great value as drug delivery system in targeting photodynamic therapy, diagnostic magnetic resonance imaging and magnetic hyperthermia therapy.

Improved mechanical properties of HIPS/hydroxyapatite composites by surface modification of hydroxyapatite via in-situ polymerization of styrene.

High impact polystyrene (HIPS)/hydroxyapatite (HA) composites are potential biomaterials for bone replacements due to their good biocompatibility and adequate mechanical properties. At the present work, the surface of the micron-sized hydroxyapatite (HA) particles was modified by in situ polymerization of styrene (St), then compounded with HIPS. The effect of the modification of HA surface on morphology and mechanical properties of HIPS/HA composites were investigated. The results showed that the HA particles does not inhibit the polymerization of St. The PS segments coated on the HA surface by in situ polymerization of St enhances the compatibility between HA and HIPS, improves the dispersion of HA particles in HIPS matrix, and enhances the interfacial adhesion between HA and matrix. Thereby, the stiffness, tensile strength and notch impact strength of HIPS/HA composites are improved at the same time. And there is a critical coating thickness of PS on the HA surface for the optimum mechanical properties of HIPS/HA composites.