Visible Light Photosensitization Research Articles

Photochemical and Enzymatic Synthesis of Malic Acid from Pyruvic Acid and HCO<sub>3</sub><sup>-</sup> with Combination System of Zinc Chlorin-e<sub>6</sub> and Malic Enzyme in Aqueous Medium

Photochemical and enzymatic synthesis of malic acid from pyruvic acid and HCO3- was studied with malic enzyme (ME) and NADP+ photoreduction with ferredoxin-NADP+-reductase (FNR) by visible light photo-sensitization of the chlorophyll derivative, zinc chlorin-e6 (ZnChl-e6), in the presence of NADH as an electron-donating reagent and methylviologen (MV2+) as an electron-relay reagent. NADPH was produced by irradiation of the reactant solution containing NADH, ZnChl-e6, MV2+, NADP+ and FNR in Bis-Tris buffer (pH 8.0). After 180-min irradiation, 8.3 mmol·dm-3 NADPH was produced under the optimum conditions with 10 mmol·dm-3 of NADP+. The reduction ratio of NADP+ to NADPH was about 83%. Malic acid was produced by irradiation with visible light (>390 nm) of the reactant solution containing NADH, ZnChl-e6, methylviologen (MV2+), pyruvic acid, NaHCO3, NADP+, ferredoxin-NADP+-reductase (FNR) and ME. Malic acid production was 2.0 mmol·dm-3 after 3-h irradiation under the optimum conditions with NADH, ZnChl-e6, MV2+, FNR, pyruvic acid, NaHCO3, NADP+ and ME. The ratio of HCO3- and pyruvic acid to malic acid was about 20% under the optimum conditions.

Synthesis and Characterization of a Magnetic Nanoemulsion as a Promising Candidate for Cancer Treatment

In this study, we performed the synthesis and characterization of a new class of drug delivery system denominated magnetic nanoemulsion (MNE), which allows the combined action of PDT and HPT therapies, designed to work in a synergic way, leading to an expected enhancement of the tumor damage after minimum doses of heat dissipation and/or visible light photosensitization. The MNPs used in this work are surface-coated with phosphate (PPT) and the photosensitizer used is Zinc phthalocyanine derivative (ZnPC). The morphologic characteristics of MNEs were investigated by transmission electron microscopy. In order to evaluate the entrapment efficiency of PS present on MNEs, we used the UV-vis spectroscopic technique. Photophysical properties of MNE/ZnPC, MNE/PPT and MNE/ZnPC/PPT were studied by time-resolved spectroscopic techniques (triplet lifetimes and singlet oxygen quantum yields). The triplet lifetimes were measured by triplet-triplet absorption flash photolysis.The decay profiles of the MNE/ZnPC and MNE/ZnPC/PPT were measured at 480 nm, under 355 nm Nd-YAG laser excitation.

Visible light and enzymatic induced synthesis of malic acid from pyruvic acid and [formula omitted] with the combination system of zinc chlorophyll derivative and malic enzyme in water media

Visible light and enzymatic induced synthesis of malic acid from pyruvic acid and HCO3- with malic enzyme (ME) and NADP+ photoreduction by the visible light photosensitization of chlorophyll derivative, zinc chlorin-e6 (Zn Chl-e6) in the presence of NADH as an electron-donating reagent was investigated. When the sample solution containing NADH, Zn Chl-e6, methylviologen (MV2+), pyruvic acid, NaHCO3, NADP+, ferredoxine-NADP+-reductase (FNR) and ME was irradiated with visible light (>390nm), malic acid was produced. The produced malic acid was 0.65mmoldm−3 after 3h visible light irradiation.

Photoinduced hydrogen production with chlorophyll-platinum nano-conjugated micellar system

Photoinduced hydrogen production with Mg chlorophyll- a (MgChl- a) from spirulina as a visible-light photosensitizer by use of three component system consisting of NADH as an electron donor, methylviologen (MV 2+) as electron relay reagent and colloidal platinum as hydrogen production catalyst in cationic surfactant, alkyltrimethyl bromide with different methylene chain length (CH 3(CH 2) n N +(CH 3) 3·Br −; n = 9, 13 and 15) micellar media is investigated. Consequently, the effective MV 2+ photoreduction and hydrogen production system is accomplished using MgChl- a in CH 3(CH 2) 15N +(CH 3) 3·Br − micellar media.

Photochemical Synthesis of Methanol from Formaldehyde Using Alcohol Dehydrogenase Coupled with Photosensitization of Zinc Porphyrin

Photochemical synthesis of methanol from formaldehyde was evaluated with alcohol dehydrogenase (ADH) from Saccharomyces cerevisiae and NAD + photoreduction by the visible light photosensitization of zinc tetraphenylporphyrin tetrasulfonate (ZnTPPS) in the presence of triethanolamine (TEOA) as an electron-donating reagent. Irradiation of a solution containing ZnTPPS, methylviologen (MV 2+ ), NAD + , diaphorase (5 units) and TEOA in potassium phosphate buffer with visible light resulted in formation of NADH increasing with time. NADH was not formed in the absence of any one of the five components, TEOA, ZnTPPS, MV 2+ , diaphorase and NAD + . The reduction ratio of NAD + to NADH reached about 60% after 180 min irradiation. Irradiation of a solution containing formaldehyde. ZnTPPS, MV 2+ , ADH, diaphorase and TEOA with visible light resulted in formation of methanol. The formaldehyde concentration decreased with formation of methanol. This result indicates that the photochemical synthesis of methanol from formaldehyde depends on ADH and NADH produced by the photosensitization of ZnTPPS. The concentration of methanol was 0.38 μmol · dm -3 after 3 h irradiation under conditions of ZnTPPS (1.0 μmol·dm -3 ), MV 2+ (0.1 mmol·dm -3 ), NAD + (0.1 mmol·dm -3 ), diaphorase (5 units), TEOA (0.3 mol·dm -3 ), formaldehyde (16 μmol·dm -3 ) and ADH (25 units).

クロロフィル誘導体と二酸化炭素固定化能を有する酵素を利用した光化学的リンゴ酸合成

Photochemical synthesis of malic acid was investigated by using pyruvic acid and CO2 with a malic enzyme (ME). NADP+ photoreduction was conducted by the visible light photosensitization of zinc chlorin-e6 (Zn Chl-e6) in the presence of NADH as an electron-donating reagent. Irradiation of a solution containing NADH, Zn Chl-e6, methylviologen (MV2+), pyruvic acid, NaHCO3, NADP+, ferredoxine-NADP-reductase (FNR) and ME with visible light resulted in malic acid synthesis. The amount of malic acid was 0.65 mmol dm-3 after 3h irradiation.

Lactic acid production with lactate dehydrogenase using the visible light sensitization of zinc porphyrin.

Lactic acid production with L-lactate dehydrogenase from Pig heart (LDH) and reduced methyl viologen produced by the visible light photosensitization of zinc tetrakis(4-methylpyridyl)porphyrin (ZnTMPyP) was investigated. When the sample solution containing triethanolamine as an electron-donating reagent, ZnTMPyP, methyl viologen as an electron carrier, pyruvic acid and LDH in potassium phosphate buffer (pH 7) was irradiated, lactic acid production was observed. After 240 min irradiation, the amount of lactic acid production and the yield of pyruvic acid to lactic acid were estimated to be 0.17 mmol dm(-3) and 17.0%, respectively.

Visible Light-induced Formic Acid Synthesis from HCO<sub>3</sub><sup>−</sup> with Formate Dehydrogenase and Water-soluble Zinc Porphyrin

Photochemical and enzymatic synthesis of formic acid was investigated from HCO 3 - with formate dehydrogenase (FDH) from Saccharomyces cerevisiae and reduced methylviologen (MV 2+ ) produced by the visible light photosensitization of zinc tetrakis(4-methylpyridyl) porphyrin (ZnTMPyP) in the presence of triethanolamine (TEOA) as an electron donating reagent. Irradiation of a solution containing TEOA, ZnTMPyP, MV 2+ , NaHCO 3 and FDH in potassium phosphate buffer, with visible light resulted in formic acid production and HCO 3 - consumption. The optimum FDH activity was 20 units and the amount of formic acid and the yield of HCO 3 - to formic acid after 4 h irradiation were estimated to be 50 μmol.dm -3 and 5.0%, respectively.

Photo-operated Glucose-O<sub>2</sub> Biofuel Cell Based on the Visible-light Photosensitization of Chlorophyll Derivatives Adsorbed on Nanocrystalline TiO<sub>2</sub> Film

A novel type of photo-operated biofuel cell was based on the combination of NAD+ reduction with glucose and GDH, with photosensitization of zinc chlorin-e6 (ZnChl-e6) as a model of chlorophyll a on a nanocrystalline TiO2 film electrode as the anode, and electrochemical reduction of oxygen to the water on a platinum electrode as the cathode. The short-circuit photocurrent (ISC) and the open-circuit photovoltage (VOC) were 6.8 μA·cm−2 and 444 mV, respectively. The peaks in the photocurrent action spectrum of this cell were observed at 400 and 780 nm, and the IPCE values at 400 and 780 nm were estimated to be approximately 11.0 and 6.2%. This novel type of photo-operated glucose-O2 biofuel cell depends on the visible and near IR photosensitization of ZnChl-e6 molecules on nanocrystalline TiO2 film electrode.

Photoinduced Hydrogen Production from Cellulose Derivative with Chlorophyll-a and Platinum Nanoparticles System

A photoinduced hydrogen production system, coupling cellulose hydrolysis by cellulase and glucose dehydrogenase (GDH) and hydrogen production with platinum nanoparticles as a catalyst using the visible light photosensitization of Mg chlorophyll-a (Mg Chl-a) from Spilurina, has been developed. When the sample solution containing cellulose derivative (methylcellulose), cellulase, nicotinamide adenine dinucleotide (NAD+), Mg Chl-a, methyl viologen (MV2+, an electron carrier reagent), and platinum nanoparticles was irradiated, continuous hydrogen production was observed with irradiation time. The amount of hydrogen production was about 12 μmol after 4 h irradiation.

Visible and near-IR light induced biohydrogen production using the system containing Mg chlorophyll-a from Spirulina and colloidal platinum.

Photoinduced hydrogen production with Mg chlorophyll-a from Spirulina as a visible and near-IR light photosensitizer by use of three component system consisting of nicotineamide adenine dinucleotide phosphate, reduced form (NADPH) as an electron donor, methylviologen as electron relay reagent and colloidal platinum as hydrogen production catalyst was investigated. After 4 h irradiation, the amount of hydrogen production with Mg chlorophyll-a and MgTPP, which was artificial model compound for chlorophyll, were c.a. 2.7 and 1.8 micromol, respectively. When the near-IR light was irradiated, little change of hydrogen production was observed. Thus, the effective visible and near IR light induced hydrogen production system with colloidal platinum was established using Mg chlorophyll-a.

Photoinduced H2 production with Mg chlorophyll-a from Spirulina and colloidal platinum by visible light

Photoinduced H2 production with Mg chlorophyll-a from Spirulina as a visible light photosensitizer by use of a three component system consisting of NADPH as an electron donor, Methyl Viologen as electron relay and colloidal platinum as catalyst was investigated. By using this system, the H2 production rate was estimated to be 0.70 ± 0.03 × 10−6 mol h−1.

Visible light induced hydrogen production with Mg chlorophyll-a from spirulina and colloidal platinum.

Photoinduced hydrogen production with Mg chlorophyll-a from spirulina as a visible light photosensitizer by use of three component system consisting of nicotineamide adenine dinucleotide phosphate, reduced form (NADPH) as an electron donor, methylviologen as electron relay reagent and colloidal platinum as hydrogen evolution catalyst was investigated. By the addition of NADPH, the photostability of Mg chlorophyll-a was increased. The effective visible-light induced hydrogen production system with colloidal platinum was established using Mg chlorophyll-a.

Bio-CO2 fixation with formate dehydrogenase from Saccharomyces cerevisiae and water-soluble zinc porphyrin by visible light

The CO2 fixation system, that is formic acid production from CO2 with FDH from Saccharomyces cerevisiae and reduced Methyl viologen produced by the visible light photosensitization of zinc tetrakis(4-methylpyridyl) porphyrin, was investigated. When the sample solution containing triethanolamine, zinc tetrakis(4-methylpyridyl) porphyrin, Methyl viologen, NaHCO3 and FDH in phosphate buffer was irradiated, formic acid was produced. The amount of formic acid production and the yield of CO2 to formic acid were estimated to be 0.104 ± 0.008 mM and 10.4%, respectively.

Properties of 2,3-butanedione and 1-phenyl-1,2-propanedione as new photosensitizers for visible light cured dental resin composites

Two 1,2-diketones, 1-phenyl-1,2-propanedione (PD) and 2,3-butanedione (BD) were investigated as new visible light photosensitizers for formulating a dental resin composite of bis-GMA in order to improve the physical properties of the resin composite. The results were then compared with those of camphorquinone (CQ), the most widely used photosensitizer. Photodecomposition of the photosensitizers with and without amine was studied through UV absorption spectroscopy. The photopolymerization efficiency of bis-GMA containing the photosensitizer increased with irradiation time and with the amount of photosensitizer. The increase was in the order: BD<CQ<PD. The experimental resin composite of bis-GMA containing BD or PD showed better mechanical properties than that which contained CQ. The reason for the higher mechanical properties of the resin composite containing BD or PD as compared with that containing CQ is discussed through the study of a model reaction. It was observed that BD or PD serves not only as a photosensitizer but also as a crosslinking agent.

Photodynamic therapy (PDT) in superficial malignomas using visible light and various photosensitizers plus minus hyperthermia

Photodynamic therapy (PDT) in superficial malignomas using visible light and various photosensitizers plus minus hyperthermia

Efficiency of opaque photoprotective agents in the visible light range

• "Opaque" physical sunscreens are important for photoprotection of individuals with visible light and UV-A photosensitivity such as those with porphyria, drug photoallergy, and polymorphous light eruption. Diffuse spectral transmittance of various thicknesses of opaque sunscreen formulations were measured from 350- to 800-nm range using a spectrophotometer equipped with an integrating sphere. Transmission through 20% zinc oxide paste was high and decreased minimally despite large increases in the sunscreen layer thickness. Adding a visible light absorber such as iron oxide to scattering sunscreens, however, substantially lowered transmittance below that predicted by the product of the transmittances for each component alone. Opaque sunscreens protected against hematoporphyrin derivative photosensitization of albino guinea pig skin; these results were quantitatively consistent with the in vitro findings. Poor photoprotection against visible light is obtained with white paste sunscreens, even if thick layers are applied. The addition of pigments to such sunscreens, however, greatly enhances photoprotection and cosmetic acceptability. (<i>Arch Dermatol.</i>1991;127:351-355)

Efficiency of Opaque Photoprotective Agents in the Visible Light Range

"Opaque" physical sunscreens are important for photoprotection of individuals with visible light and UV-A photosensitivity such as those with porphyria, drug photoallergy, and polymorphous light eruption. Diffuse spectral transmittance of various thicknesses of opaque sunscreen formulations were measured from 350- to 800-nm range using a spectrophotometer equipped with an integrating sphere. Transmission through 20% zinc oxide paste was high and decreased minimally despite large increases in the sunscreen layer thickness. Adding a visible light absorber such as iron oxide to scattering sunscreens, however, substantially lowered transmittance below that predicted by the product of the transmittances for each component alone. Opaque sunscreens protected against hematoporphyrin derivative photosensitization of albino guinea pig skin; these results were quantitatively consistent with the in vitro findings. Poor photoprotection against visible light is obtained with white paste sunscreens, even if thick layers are applied. The addition of pigments to such sunscreens, however, greatly enhances photoprotection and cosmetic acceptability.

Inhibition of Human Lymphocyte Stimulation by Visible Light and Phthalocyanine Photosensitization: Mitogen and Wavelength Dependency

Mitogenic stimulation of human peripheral blood lymphocytes is inhibited by phthalocyanine photosensitization using visible light. The mechanism of inhibition was studied using stimulating agents differing in their mode of action. Stimulation by the plant lectin phytohemagglutinin (PHA) was the least sensitive to inhibition by photosensitization, followed by the tumor promoter phorbol myristate acetate (PMA) and the calcium ionophore A23187. Mitogenic stimulation could also be inhibited by light only, but higher fluences were needed. The order of efficacy was blue greater than red greater than green light, and the response to A23187 was least affected, followed by an increased inhibition of the response to PHA and PMA stimulation. Possible targets and mechanisms for these effects are discussed.

Photographic image storage in ion implanted PLZT ceramics

Photographic images can be stored in transparent lead lanthanum zirconate titanate (PLZT) ceramics using near-UV light with photon energies near the band gap energy of 3.42 eV. Coimplanting inert ions, e.g., Ar, Ne and He, into the surface exposed to image light can increase near-UV photosensitivity by a factor of almost 10 4, with no degradation of image quality, so that the exposure energy threshold is reduced from ∼ 100 mJ/cm 2 to ∼ 10 μJ/cm 2. Coimplanting chemically active and inert ions, e.g., Al or Ne, can result in similar improvement of the extrinsic (visible light) photosensitivity and in an essentially flat photoresponse from about 400 to 600 nm. In addition, thermal diffusion of Al followed by Ne implantation yield photosensitivity increases in the near-UV comparable to the best results obtained to date with ion implantation. The Al-diffused plus Ne-implanted samples also have the highest photosensitivity obtained to date in the blue region of the visible spectrum. Ion implanted, or Al-diffused plus Ne implanted, PLZT is now the most sensitive, nonvolatile but selectively erasable image storage medium known to exist.