Yingxue Jin

Facile synthesis of chitosan assisted multifunctional magnetic Fe3O4@SiO2@CS@pyropheophorbide-a fluorescent nanoparticles for photodynamic therapy

Novel chlorin photosensitizer pyropheophorbide-a (PPA) coated multifunctional magneto-fluorescent nanoparticles Fe3O4@SiO2@CS@PPA (MFCSPPA) about 50 nm in diameter were strategically designed and prepared for photodynamic therapy (PDT) based on the good solubility and magnetic targeting of Fe3O4@SiO2 nanoparticles, excellent biocompatibility and biodegradability of chitosan (CS) polymer, and the unique fluorescence and photodynamic activity of pyropheophorbide-a. In this work, we found that magneto-fluorescent MFCSPPA has high saturation magnetization of 23.7 emu g−1, and showed super-paramagnetic properties, good dispersion in alcohol and water, excellent water-solubility, improved biocompatibility and good photoluminescence properties. In addition, we demonstrated MFCSPPA mediated singlet oxygen production in solution conditions by using 1,3-diphenylisobenzofuran (DPBF) as a fluorescence detector. Moreover, the in vitro PDT activities against human HeLa cervical cancer cells were investigated by MTT assay. The phototoxicity experiments showed that MFCSPPA has strong photodynamic therapy activity and low dark toxicity, and the cancer cell viability was reduced to 18% after treatment with PDT. Phagocytosis of MFCSPPA experiments indicated that it could be successfully taken up to some extent by HeLa cells with a suitable lipo-hydro partition coefficient and biocompatibility. Acridine orange/ethidium bromide (AO/EB) double fluorescence staining suggested that the cells are all in a state of apoptosis or necrosis after PDT treatment for 6 h. In addition, we studied the formation of reactive oxygen species in HeLa cells after MFCSPPA-PDT treatment; the results suggested that type I and type II photodynamic reactions can occur simultaneously, yet type I photodynamic reactions have a slight edge over type II. The as-prepared magneto-fluorescent MFCSPPA nanoparticles are suitable for simultaneous PDT and medical fluorescence imaging.

An Amidochlorin-Based Colorimetric Fluorescent Probe for Selective Cu(2+) Detection.

The design and synthesis of selective and sensitive chemosensors for the quantification of environmentally and biologically important ionic species has attracted widespread attention. Amidochlorin p6 (ACP); an effective colorimetric and fluorescent probe for copper ions (Cu2+) in aqueous solution derived from methyl pheophorbide-a (MPa) was designed and synthesized. A remarkable color change from pale yellow to blue was easily observed by the naked eye upon addition of Cu2+; and a fluorescence quenching was also determined. The research of fluorescent quenching of ACP-Cu2+ complexation showed the detection limit was 7.5 × 10−8 mol/L; which suggested that ACP can act as a high sensitive probe for Cu2+ and can be used to quantitatively detect low levels of Cu2+ in aqueous solution. In aqueous solution the probe exhibits excellent selectivity and sensitivity toward Cu2+ ions over other metal ions (M = Zn2+; Ni2+; Ba2+; Ag+; Co2+; Na+; K+; Mg2+; Cd2+; Pb2+; Mn2+; Fe3+; and Ca2+). The obvious change from pale yellow to blue upon the addition of Cu2+ could make it a suitable “naked eye” indicator for Cu2+.

Preparation, characterization and in vitro photodynamic therapy of a pyropheophorbide-a-conjugated Fe3O4 multifunctional magnetofluorescence photosensitizer

Novel pyropheophorbide-a-conjugated multifunctional magnetofluorescence nanoparticles Fe3O4@SiO2@APTES@Glutaryl-PPa (MFNPs) with a mean diameter of 50 nm were strategically designed and prepared for photodynamic therapy (PDT) and medical fluorescence imaging. Chlorin photosensitizer pyropheophorbide-a (PPa) was covalently anchored on the surface of core–shell Fe3O4@SiO2@APTES nanoparticles that were prepared via a sol–gel process with a bridging glutaryl group. The phase constitution, morphology, size, chemical properties, magnetic property of the intermediates and final nanoparticles were characterized by X-ray powder diffraction, transmission electron microscopy, Fourier transform infrared spectrometer, zeta potential, vibration sample magnetometer, thermogravimetric analysis, ultraviolet-visible absorption spectra and fluorescent emission spectroscopy. These results showed that the MFNPs have good dispersibility in alcohol and water, excellent magnetization with 17.31 emu g−1 at 300 K, strong superparamagnetic and good photoluminescence property. The in vitro PDT against the human HeLa cervical cancer cell suggested that MFNPs could permeate the tumor cells quickly and possess suitable lipo-hydro partition coefficient, inducing damage and apoptotic cell death. The cancer cell viability was lowered to 10.18% after treatment with PDT. In addition, the formation of reactive oxygen species in HeLa cells after MFNPs-PDT treatment was studied, which suggested that Type I and Type II photodynamic reactions can occur simultaneously.

A Novel Photosensitizer 31,131-phenylhydrazine -Mppa (BPHM) and Its in Vitro Photodynamic Therapy against HeLa Cells

Photodynamic therapy (PDT) has attracted widespread attention due to its potential in the treatment of various cancers. Porphyrinic pyropheophorbide-a (PPa) has been shown to be a potent photosensitizer in PDT experiments. In this paper, a C-31,131 bisphenylhydrazone modified methyl pyropheophorbide-a (BPHM) was designed and synthesized with the consideration that phenylhydrazone structure may extend absorption wavelength of methyl pyro-pheophorbide-a (Mppa), and make the photosensitizer potential in deep tumor treatment. The synthesis, spectral properties and in vitro photodynamic therapy (PDT) against human HeLa cervical cancer cell line was studied. Methyl thiazolyl tetrazolium (MTT) assay showed the title compound could achieve strong inhibition of cervical cancer cell viability under visible light (675 nm, 25 J/cm2). Cell uptake experiments were performed on HeLa cells. Morphological changes were examined and analyzed by fluorescent inverted microscope. In addition, the mechanism of the photochemical processes of PDT was investigated, which showed that the formation of singlet oxygen after treatment with PDT played a moderate important role.

Synthesis and in vitro photodynamic therapy of chlorin derivative 13(1)-ortho-trifluoromethyl-phenylhydrazone modified pyropheophorbide-a.

Photodynamic therapy (PDT) is entering the mainstream of the cancer treatments recently. Pyropheophorbide-a (Pa), as a degradation product of chlorophyll-a, has been shown to be a potent photosensitizer in photodynamic therapy. In this paper, we investigated the in vitro photodynamic therapy of 131-ortho-trifluoromethyl-phenylhydrazone modified pyropheophorbide-a (PHPa) against human HeLa cervical cancer cell line, together with ultraviolet-visible spectra, fluorescence emission spectra, stability in various solvents, and single oxygen quantum yield. The results indicated that PHPa not only showed a greater molar extinction coefficient reached 4.55×104 Lmol-1cm-1, the long absorption wavelength (681nm) as we expected that makes it potential in deep tumor treatment, but also showed better stability in near neutral phosphate buffers (pH 7.4) and culture medium, as well as higher single oxygen quantum yield (ФD=40.5%) in DMF solutions. Moreover, cell experiments suggested that PHPa could be uptaken by HeLa cells successfully, and has low dark toxicity without irradiation, but remarkable photo-cytotoxicity (IC50, 1.92±0.59μM) that the inhibition rate of HeLa cells could increase up 91.4% at 30μM of PHPa after irradiation. In addition, morphological changes of HeLa cells further demonstrated that PHPa can induce damage and apoptotic cell death. Furthermore, the mechanism of photochemical processes was investigated by using specific quenching agent sodium azide (SA) and D-mannitol (DM), respectively, which showed the formation of singlet oxygen (Type II reaction mechanism) may play a predominant role, Type I and Type II photodynamic reactions could occur simultaneously in this PHPa mediated PDT process.

Magnetic iron oxide modified pyropheophorbide-a fluorescence nanoparticles as photosensitizers for photodynamic therapy against ovarian cancer (SKOV-3) cells.

Magnetic iron oxide modified pyropheophorbide-a fluorescence nanoparticles, Fe3O4@SiO2@APTES@PPa (FSAP), were designed as magnetically targeted photodynamic antineoplastic agents and prepared through continuous covalent chemical modification on the surface of Fe3O4 nanoparticles. The properties of the intermediates and the final product were comprehensively characterized by transmission electron microscopy, powder X-ray diffraction analysis, Fourier transform infrared spectroscopy, vibrating sample magnetometry, zeta potential measurement, ultraviolet-visible absorption spectroscopy, fluorescence emission spectroscopy, and thermogravimetric analysis. In this work, we demonstrated the in vitro photodynamic therapy (PDT) of FSAP against ovarian cancer (SKOV-3) cells, which indicated that FSAP could be taken up successfully and showed low dark toxicity without irradiation, but remarkable phototoxicity after irradiation. Meanwhile, FSAP had showed good biocompatibility and low dark toxicity against normal cells in the biological experiments on mouse normal fibroblast cell lines (L929 cells). In addition, in the photochemical process of FSAP mediated photodynamic therapy, the Type-II photo-oxygenation process (generated singlet oxygen) played an important role in the induction of cell damage.

Magnetic chitosan/graphene oxide composite loaded with novel photosensitizer for enhanced photodynamic therapy

Photodynamic therapy (PDT) is an increasingly recognized alternative to treat various cancers in clinical practice. Most second-generation photosensitizers (PS) are hydrophobic and have poor targeting selectivity, which limit their efficacy for PDT. In this paper, graphene oxide (GO) coupled with magnetic Fe3O4 nanoparticles and chitosan (CS) (MCGO) was prepared by a one-pot solvothermal method and used as a nanocarrier for loading the new photosensitizer HNPa (λmax = 698 nm), which was first synthesized by our group, and was considered as a good water-soluble drug and an excellent tissue-penetrating agent due to its strong absorption at 698 nm (near-infrared region). The synthesized composite (MCGO–HNPa) showed high stability, good water solubility and biocompatibility, expected magnetic targetability, and good photostability for PDT even in low concentrations. Our research reveals that MCGO nanomaterials can promote the production and release of singlet oxygen (ΦΔ = 62.9%) when compared with free HNPa. In addition, the in vitro cell uptake experiments suggested that the MCGO nanomaterials can accelerate the penetration of HNPa drugs into the tumor cell nucleus and that the drug release behavior is pH-sensitive. The MTT assay results against human hepatoma cell lines HepG-2 clearly show that the MCGO–HNPa composite can effectively result in cell damage and apoptotic cell death under light, and that the nanocomposite can improve the PDT antitumor effect of PS agents with negligible dark toxicity. Meanwhile, the research on the photoreaction mechanism reveals that Type I and Type II photodynamic reactions can occur simultaneously in this PDT process, and their relative contributions depend on the type and dose of the photosensitizer. Type II has a greater effect on PDT than Type I, especially for a higher HNPa photosensitizer dose. All the results reveal the promising application of the presented novel strategy.

The anti-cancer potency of photodynamic therapy of a novel chlorin derivative Amidochlorin p6 (ACP)

Photodynamic therapy (PDT) is a minimally invasive method in cancer treatment and has attracted considerable attention recently. In this paper, we have performed a detailed study of photodynamic activity of a chlorophyllous derivative, Amidochlorin p6 (ACP), and evaluated its potential as a photosensitizer in PDT. The singlet oxygen quantum yield (ΦΔ), the photoreaction mechanisms in PDT, the anti-photobleaching ability in phosphate buffer saline (PBS), the photocytotoxicity and dark toxicity against HeLa cells, cellular uptake and the influence on the expression of survivin and cyclin-dependent kinase (CDK2), were all investigated. The title compound showed significant photocytotoxicity and negligible toxicity in dark, and remarkable photostability. Moreover, ACP could be uptaken by HeLa cells successfully at 20 min leading to damage of cancer cells under light, during which Type I and Type II photodynamic reactions occurred simultaneously on HeLa cells in PDT treatment, and the influence of Type I (the generation of hydroxyl radicals) is slightly larger than Type II (the generation of singlet oxygen). In addition, real-time fluorescent quantitative PCR (RT-qPCR) suggested that ACP could significantly regulate the expression of survivin, which partly explained why ACP could induce the HeLa cell apoptosis and accelerate cell death.

Facile synthesis of a highly water-soluble graphene conjugated chlorophyll-a photosensitizer composite for improved photodynamic therapy in vitro

In photodynamic therapy (PDT), selection of an ideal photosensitizer and improvement of its photodynamic activities are currently of great interest. In this work, a chlorophyll-a photosensitizer derivative, p-bromo-phenylhydrazone-methyl pyropheophorbide-a (BPMppa) with a long absorption wavelength (683 nm) and a large molar extinction coefficient (7.03 × 104 M−1 cm−1), which is considered to be more suitable for the treatment of deep cancer, is loaded onto pristine graphene using a direct graphite exfoliation process via π–π stacking in water. The obtained graphene loaded photosensitizer G–BPMppa composite shows significantly improved water-solubility and dispersity in water, PBS and culture medium, and an increased singlet oxygen (1O2) quantum yield (ΦΔ = 60.55%) in DMF solution compared to free BPMppa (ΦΔ = 29.2%). In addition, cell experiments indicated that the G–BPMppa composite could be taken up by HeLa cells successfully, showing enhanced intracellular uptake behavior. Owing to its enhanced intracellular uptake and higher 1O2 quantum yield, G–BPMppa showed remarkably improved PDT efficiency (IC50: 1.36 ± 0.35 μg mL−1 of equivalent BPMppa) over free BPMppa after irradiation, but low dark toxicity without irradiation. Moreover, cell morphological changes after G–BPMppa PDT further qualitatively demonstrated that G–BPMppa could induce damage and apoptotic cell death efficiently. Furthermore, the photochemical mechanism of the G–BPMppa mediated PDT process was investigated by using specific quenching agents, sodium azide (SA, a singlet oxygen quencher) and D-mannitol (DM, a hydroxyl radical quencher); the results indicated that type I and type II photodynamic reactions could occur simultaneously, yet the type II reaction (the generation of 1O2) might play a predominant role in the G–BPMppa induced PDT process.

pH-Sensitive graphene oxide conjugate purpurin-18 methyl ester photosensitizer nanocomplex in photodynamic therapy

Graphene oxide (GO) has been widely recognized as a good drug delivery vector due to its special properties and biocompatibility. Herein, a promising chlorophyll-a derivative photosensitizer, purpurin-18 methyl ester (Pu18), was introduced onto the surface of GO to investigate the drug loading and release properties. Pu18 is considered to be more suitable for the treatment of deeper tissues due to its strong absorption in the near infrared region (Q(0,0) band at 699 nm). The graphene oxide loaded Pu18 nanomaterial (GO–Pu18) was obtained via simple ultrasonic agitation and presented pH-sensitive drug release behavior. Pu18 could be released more easily from the GO–Pu18 composite in a weak acid environment than that in a neutral environment, suggesting that GO–Pu18 could be applied in tumor treatment due to the weak acid environment around tumor tissues. Moreover, GO–Pu18 showed an increased singlet oxygen (1O2) quantum yield (ΦΔ = 62.60%) compared to free Pu18 (ΦΔ = 58.82%) and showed remarkable photostability in phosphate buffer saline (PBS). In vitro experiments on HepG-2 cells showed that the GO–Pu18 composite possessed excellent photocytotoxicity and negligible dark toxicity. Cell morphological changes after PDT treatment also showed that GO–Pu18 could lead to remarkable damage of cancer cells under light, during which Type I (the generation of hydroxyl radicals) and Type II (the generation of singlet oxygen) photodynamic reactions occurred simultaneously, yet the Type II reaction might play a predominant role. The research has disclosed that the new composite GO–Pu18a is a favorable prospect in the treatment of PDT.