Yiru Peng

Effect of axial ligands on the photophysical properties of new silicon(IV) phthalocyanines

A series of axial di-substituted silicon(IV) phthalocyanines with electron-donating and electron-withdrawing properties were synthesized. The compounds were characterized by elemental analysis, 1H NMR, IR, and ESI-MS. The effect of axial ligands on the photophysical properties of silicon phthalocyanines was studied by UV/Vis, steady-state and time-resolved fluorescence spectroscopic analyses. Compared with silicon phthalocyanines with electron-donating properties, silicon phthalocyanines with electron-withdrawing properties could expand the π-conjugation in the dyes, resulting in a redshift of Q bands, lower fluorescence emission intensity and fluorescence quantum yields, but increasing fluorescence lifetimes. These results strongly suggest that the molecular design of phthalocyanines is essential for construction of photoactive materials.

Benzophenone and zinc(II) phthalocyanine dichromophores-labeled poly (aryl ether) dendrimer: synthesis, characterization and photoinduced energy transfer

Abstract A series of benzophenone chromospheres and zinc(II) phthalocyanine dichromophores labeled poly (aryl benzyl ether) dendrimer (Gn-DZnPc(BP)8n, n = 1−2) were synthesized. Their structures were characterized by elemental analysis, 1H NMR, IR, UV–vis and matrix-assisted laser desorption/ionization time-of-flight spectrometry (MALDI-TOF MS). Their photophysical properties were examined by steady-state and time-resolved fluorescence methods. Both the poly (aryl benzyl ether) dendrimer and BP terminal chromophores had a significant effect on photophysical properties of the zinc(II) phthalocyanine core. Time-resolved spectroscopic measurements indicated that the lifetime of benzophenone (donor) chromophore was longer than that of the zinc(II) phthalocyanine (acceptor). The fluorescence of the peripheral benzophenone chromophores was quenched by the phthalocyanine group attached to the focal point. All of these observations suggest that an intramolecular singlet energy transfer occurs in Gn-DZnPc(BP)8n molecules. The light-harvesting abilities of these molecules increased with generations due to an increase in the number of benzophenone chromophores. The energy transfer efficiencies were ca. 0.49 and 0.68 for generations 1 and 2, respectively, and the rate constants of the singlet-singlet energy transfer were ca. 108 s−1. The rate constants changed inconspicuously with increase of dendron generations. The intramolecular singlet-singlet energy transfer is proposed to proceed mainly via a Förster-type interaction mechanism involving the dendrimer backbone as a scaffold to hold the peripheral benzophenone chromophores and the phthalocyanine core together. This dendrimer was an effective new energy transmission complex with high efficiency and could be used as a potential light-harvesting system.

Spectroscopic analysis of the interaction between tetra-(p-sulfoazophenyl-4-aminosulfonyl)-substituted aluminum (III) phthalocyanines and serum albumins

The binding interaction between tetra-(p-sulfoazophenyl-4-aminosulfonyl)-substituted aluminum (III) phthalocyanine (AlPc), and two-serum albumins (bovine serum albumin (BSA) and human serum albumin (HSA)) has been investigated. AlPc could quench the intrinsic fluorescence of BSA and HSA through a static quenching process. The primary and secondary binding sites of AlPc on BSA were domain I and III of BSA. The primary binding site of AlPc on HSA was domain I, and the secondary binding sites of AlPc on HSA were found at domains I and II. Our results suggest that AlPc readily interact with BSA and HSA implying that the amphiphilic substituents AlPc may contribute to their transportation in the blood.

Photophysical property of a polymeric nanoparticle loaded with an aryl benzyl ester silicon (IV) phthalocyanine

Because of their excellent near-infrared (NIR) optical properties, phthalocyanines (Pcs) have been regarded as promising therapy agents for fluorescence image-guided drug delivery and noninvasive treatment of tumors by photodynamic therapy (PDT). Nevertheless, phthalocyanines are substantially limited in clinical applications owing to their poor solubility, aggregation and insufficient selectivity for cancer cells. To address these issues, we have developed a novel dendrimer-based theranostic nanoparticle for tumor-targeted delivery of phthalocyanine. The preparation procedure involved the modification of the silicon (IV) phthalocyanine molecule with a dendritic axially substitution, which significantly enhances their photophysical property. In order to improve biocompatibility and tumor-targeted delivery, the hydrophobic dendritic phthalocyanine was encapsulated by diblock amphiphilic copolymer poly (ethylene glycol)-poly (Epsilon-caprolactone) (MPEG-PCL) to form a polymeric nanoparticle. The polymeric nanoparticle is spherical with a diameter at about 90 nm. The photophysical property of the polymeric nanoparticle was studied by UV/Vis and fluorescence spectroscopic methods. Compared with the free dendritic phthalocyanine, the Q band of the polymeric nanoparticle was red-shifted, and the fluorescence intensity decreased. Furthermore, the polymeric nanoparticle has a relatively high loading amount and encapsulation rate. Therefore, the polymeric nanoparticle would be a promising third-generation photosensitizer (PS) for PDT.

Polyion complex micelles incorporating poly (aryl benzyl ether) dendritic phthalocyanine: effective photosensitizers for enhanced photodynamic therapy

A novel series of zinc (II) phthalocyanines bearing four poly (aryl benzyl ether) dendritic substituents with carboxylic acid functionalities (Gn-DPcZn (Gn=n-generation dendrimer, n=1-2)) loaded polymeric micelles (Gn-DPcZn/m) were formed. The time-dependent intracellular uptake of Gn-DPcZn in RPE cells increased as they were incorporated into micelles, but inversely correlated with the generation. The photocytoxity of Gn-DPcZn was improved by incorporation into polymeric micelles and increased with the generation.

Photophysical properties of dendrimer phthalocyanine-functionalized single-walled carbon nanotubes

The photophysical properties of a novel series dendrimer phthalocyanine-SWNTs nanoconjugates in which the dendrimer phthalocyanine was tetra-[3,5-di-(4-carboxylic benzyloxy)benzyloxy] zinc(Ⅱ) phthalocyanine covalently linked with SWNTs using ethylenediamine or hexamethylenediamine as space linkers were investigated in detailed by the fluorescent spectra and time-resolved spectroscopy. The photoindued intramolecular electron was transferred from phthalocyanine (donor) to carbon nanotubes (acceptor). Novel functionalized constituents in this work are fundamentally important due to the synergy effects of carbon nanotubes and dendritic zinc phthalocyanine, which may find potential applications in the drug delivery, biological labels and many other related fields.

Photophysical properties of pyridyloxy phthalocyanine encapsulated in nanoparticles

Abstract Two aluminum chloride phthalocyanines with pyridyloxy substitution at α/β positions were synthesized. Their structures were characterized by infrared spectroscopy, proton nuclear magnetic resonance as well as elemental analysis. Tetra-α(β)-(2-pyridyloxy) aluminum chloride phthalocyanines were encapsulated into a diblock copolymer methoxy-poly(ethylene glycol)-block-poly(L-lysine) through a cosolvent method. The morphologies and photophysical properties of phthalocyanines encapsulated in nanoparticles were studied by transmission electron microscope, ultraviolet-visible, and fluorescence spectroscopic methods. The photophysical properties of phthalocyanines encapsulated into nanoparticles exhibited substitution positions dependence. The phthalocyanines with substitution at α positions were found to be an excellent candidate for use as photosensitizers for treatment of cancer by photodynamic therapy.

Metronidazole-substituted dendrimer silicon phthalocyanine: a novel photodynamic therapy photosensitizer

As an excellent second-generation photosensitizer for photodynamic therapy (PDT), phthalocyanine (Pc) complex has strong absorption peak in the near-infrared region and strong tissue penetrating ability, which endowed them excellent properties for the detection of tumor tissue. In recent years, in order to further ehnaced the penetration depth of the photosensitizer to the tissue, a large number of functional groups have been synthesized . In this work, we designed and synthesized metronidazole-substituted dendrimer silicon phthalocyanine (MT-SiPc) with near-infrared region Q-band of UV absorption, excellent fluorescence properties and photochemical properties.

Effect of curcumin-loaded nanoparticles on mitochondrial dysfunctions of breast cancer cells

Curcumin exhibits excellent anticancer and antibacterial activities. However, this compound has poor solubility and lower bioavailability, which limits its therapeutic efficacy. To improve its anticancer effects, a novel curcumin nanoparticle system using a diblock copolymer MPEG-PCL as a nanocarrier was prepared by a self-assemble method. This novel nanoparticle was applied to assess the cellular uptake and drug cytotoxicity of the breast cancer cells MDA-MB-231. Furthermore, dysfunction of mitochondria during drug treatment was studied by confocal imaging. The results showed that the curcumin-loaded nanoparticles had a preferential uptake in the MDA-MB-231 cells and had a significant increased cytotoxicity compared to curcumin. The nanoparticle can induce fragment of mitochondria, loss of mitochondrial membrane potential, and increment of reactive oxygen species, which indicated the apoptosis of cells increased. In addition, intravenous application of curcumin-loaded nanoparticles inhibited the growth of MDA-MB-231 breast carcinoma in vivo and exhibited a stronger anticancer ability in comparison to free curcumin. Our present findings clearly demonstrate that the curcumin-loaded nanoparticles display an improved anticancer effect via mitochondria-mediated apoptosis pathway, which may be a potential utilization for cancer therapy.

The effect of the triblock properties on the morphologies and photophysical properties of nanoparticle loaded with carboxylic dendrimer phthalocyanine

Photodynamic therapy (PDT) is an emerging alternative treatment for various cancers and age-related macular degeneration. Phthalocyanines (Pcs) and their substituted derivatives are under intensive investigation as the second generation photosensitizers. A big challenge for the application of Pcs is poor solubility and limited accumulation in the tumor tissues, which severely reduced its PDT efficacy. Nano-delivery systems such as polymeric micelles are promising tools for increasing the solubility and improving delivery efficiency of Pcs for PDT application. In this paper, nanoparticles of amphiphilic triblock copolymer poly(L-lysine)-b-poly (ethylene glycol)-b-poly(L-lysine) were developed to encapsulate 1-2 generation carboxylic poly (benzyl aryl ether) dendrimer. The morphologies and photophysical properties of polymeric nanoparticles loaded with 1-2 generation dendritic phthalocyanines (G1-ZnPc(COOH)8/m and G2-ZnPc(COOH)16/m) were studied by AFM, UV/Vis and fluorescent spectroscopic method. The morphologies of self-assembled PLL-PEG-PLL aggregates exhibited concentration dependence. Its morphologies changed from cocoon-like to spheral. The diameters of G1-ZnPc(COOH)8/m and G2-ZnPc(COOH)16/m were in the range of 33-147 nm, increasing with the increase of the concentration of PLL-PEG-PLL. The morphologies of G2-ZnPc(COOH)16/m also changed from cocoon-like to sphere with the increase of the concentration of PLL-PEG-PLL. It was found that, the no obviously Q change was observed between the free phthalocyanines and nanoparticles. The fluorescence intensity of polymer nanoparticles were higher enhanced compared with free dendritic phthalocyanines. The dendrimer phthalocyanine loaded with poly(L-lysine)-b-poly (ethylene glycol)-b-poly(L-lysine) presented suitable physical stability, improved photophysical properties suggesting it may be considered as a promising formulation for PDT.