Amphiphilic tricationic Zn(II)phthalocyanine provides effective photodynamic action to eradicate broad-spectrum microorganisms

A novel tricationic Zn(II)phthalocyanine derivative, (NCH3)3ZnPc3+, was synthesized by ring expansion reaction of boron(III) [2,9(10),16(17)-trinitrosubphthalocyaninato]chloride. First, the reaction of this subphthalocyanine with 2,3-naphthalenedicarbonitrile and Zn(CH3COO)2 catalyzed by 8-diazabicyclo[5.4.0]undec-7-ene was used to obtain the A3B-type nitrophthalocyanine. After reduction of nitro groups with Na2S and exhaustive methylation of amino groups, (NCH3)3ZnPc3+ was formed in good yields. In addition, the tetracationic analog (NCH3)4ZnPc4+ was synthesized to compare their properties. The absorption and fluorescence spectra showed the Q-bands and the red emission, respectively, which are characteristic of the Zn(II)phthalocyanine derivatives in N,N-dimethylformamide. Furthermore, photodynamic activity sensitized by these compounds was studied in the presence of different molecular probes to sense the formation of reactive oxygen species. (NCH3)3ZnPc3+ efficiently produced singlet molecular oxygen and also it sensitized the formation of superoxide anion radical in the presence of NADH, while the photodynamic activity of (NCH3)4ZnPc4+ was very poor, possibly due to the partial formation of aggregates. Furthermore, the decomposition of L-tryptophan induced by (NCH3)3ZnPc3+ was mainly mediated by a type II mechanism. Antimicrobial photodynamic inactivation sensitized by these phthalocyanines was evaluated in Staphylococcus aureus, Escherichia coli, and Candida albicans, as representative microbial cells. In cell suspensions, (NCH3)3ZnPc3+ was rapidly bound to microbial cells, showing bioimages with red fluorescence emission. After 5 min of irradiation with visible light, (NCH3)3ZnPc3+ was able to completely eliminate S. aureus, E. coli and C. albicans, using 1.0, 2.5 and 5.0 μM phthalocyanine, respectively. In contrast, a low photoinactivation activity was found with (NCH3)4ZnPc4+ as a photosensitizer. Therefore, the amphiphilic tricationic phthalocyanine (NCH3)3ZnPc3+ is a promising photosensitizing structure for application as a broad-spectrum antimicrobial phototherapeutic agent.Fil: Baigorria, Estefanía. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Durantini, Javier Esteban. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados; ArgentinaFil: Di Palma, María Albana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; ArgentinaFil: Gsponer, Natalia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; ArgentinaFil: Milanesio, María Elisa. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Durantini, Edgardo Néstor. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentin

Magnetic Nanoplatforms for in Situ Modification of Macromolecules: Synthesis, Characterization, and Photoinactivating Power of Cationic Nanoiman-Porphyrin Conjugates

A nanoplatform concept was developed to synthesize accessible photoactive magnetic nanoparticles (MNPs) of Fe3O4 coated with silica. This approach was based on the covalent binding of 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin (TPPF20) to aminopropyl-grafted MNPs by nucleophilic aromatic substitution reaction (SNAr) to obtain conjugate MNP-P1. After in situ modification, the remaining pentafluorophenyl groups of TPPF20 attached to MNPs were substituted by dimethylaminoethoxy groups to form MNP-P2. The basic amine group of these conjugates can be protonated in aqueous media. In addition, MNP-P1 and MNP-P2 were intrinsically charged to produce cationic conjugates MNP+-P1 and MNP+-P2+ by methylation. All of them were easily purified by magnetic decantation in high yields. The average size of the MNPs was ∼15 nm, and the main difference between these conjugates was the greater coating with positive charges of MNP+-P2+, as shown by the zeta potential values. Absorption spectra exhibited the Soret and Q bands characteristic of TPPF20 linked to MNPs. Furthermore, these conjugates showed red fluorescence emission of porphyrin with quantum yields of 0.011-0.036. The photodynamic effect sensitized by the conjugates indicated the efficient formation of singlet molecular oxygen in different media, reaching quantum yield values of 0.17-0.34 in N,N-dimethylformamide. The photodynamic activity of the conjugates was evaluated to inactivate the Gram-positive bacteria Staphylococcus aureus, the Gram-negative bacteria Escherichia coli, and the yeast Candida albicans. The modified cationic MNP+-P2+ was the most effective conjugate for photodynamic inactivation (PDI) of microorganisms. Binding of this conjugate to bacteria and photoinactivation capability was checked by means of fluorescence microscopy. Also, sustainable use by recycling was determined after three PDI treatments. Therefore, this methodology is a suitable scaffold for the in situ modification of conjugates, and in particular, MNP+-P2+ represents a useful photodynamic active material to eradicate microorganisms.Fil: Scanone, Ana Coral. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Gsponer, Natalia Soledad. Universidad Nacional de Río Cuarto. Instituto para el Desarrollo Agroindustrial y de la Salud. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto para el Desarrollo Agroindustrial y de la Salud; ArgentinaFil: Alvarez, María Gabriela. Universidad Nacional de Río Cuarto. Instituto para el Desarrollo Agroindustrial y de la Salud. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto para el Desarrollo Agroindustrial y de la Salud; ArgentinaFil: Heredia, Daniel Alejandro. Universidad Nacional de Río Cuarto. Instituto para el Desarrollo Agroindustrial y de la Salud. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto para el Desarrollo Agroindustrial y de la Salud; ArgentinaFil: Durantini, Andres Matías. Universidad Nacional de Río Cuarto. Instituto para el Desarrollo Agroindustrial y de la Salud. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto para el Desarrollo Agroindustrial y de la Salud; ArgentinaFil: Durantini, Edgardo Néstor. Universidad Nacional de Río Cuarto. Instituto para el Desarrollo Agroindustrial y de la Salud. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto para el Desarrollo Agroindustrial y de la Salud; Argentin

Diketopyrrolopyrrole-fullerene C60 architectures as highly efficient heavy atom-free photosensitizers: Synthesis, photophysical properties and photodynamic activity

Chromophore-fullerene C60 hybrids possess interesting properties that enable them to act as heavy atom-free photosensitizers and reactive oxygen species (ROS) producers. Here, two new diketopyrrolopyrrole-C60 conjugates were efficiently synthesized and characterized. The conjugates show broadband absorption in the visible spectral region, in which diketopyrrolopyrrole dyes act as light-harvesting antenna with very high capacity to populate excited triplet states. Furthermore, the ability of diketopyrrolopyrrole-C60 systems to generate singlet molecular oxygen was explored for the first time in solvents of different polarities. The experimental results show that these architectures exhibit very high production rates of this ROS. In addition, a preliminary study on Staphylococcus aureus cell suspensions indicates that both conjugates exhibit phototoxicity after irradiation with green LED light. Thus, the data obtained provide evidence that these diketopyrrolopyrrole-C60 architectures act as potential heavy atom-free photosensitizers in photodynamic inactivation of microorganisms and other singlet oxygen-mediated applications.Fil: Agazzi, Maximiliano Luis. Universidad Nacional de Río Cuarto. Instituto para el Desarrollo Agroindustrial y de la Salud. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto para el Desarrollo Agroindustrial y de la Salud; ArgentinaFil: Almodovar, Vitor A. S.. Universidade de Aveiro; PortugalFil: Gsponer, Natalia Soledad. Universidad Nacional de Río Cuarto. Instituto para el Desarrollo Agroindustrial y de la Salud. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto para el Desarrollo Agroindustrial y de la Salud; ArgentinaFil: Bertolotti, Sonia Graciela. Universidad Nacional de Río Cuarto. Instituto para el Desarrollo Agroindustrial y de la Salud. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto para el Desarrollo Agroindustrial y de la Salud; ArgentinaFil: Tomé, Augusto C.. Universidade de Aveiro; PortugalFil: Durantini, Edgardo Néstor. Universidad Nacional de Río Cuarto. Instituto para el Desarrollo Agroindustrial y de la Salud. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto para el Desarrollo Agroindustrial y de la Salud; Argentin

Effects of divalent cations, EDTA and chitosan on the uptake and photoinactivation of Escherichia coli mediated by cationic and anionic porphyrins

The effect of divalent cations, EDTA and chitosan (CS) on the uptake and photoinactivation of Escherichia coli produced by 5,10,15,20-tetrakis(4-N,N,N-trimethylammoniumphenyl)porphyrin (TMAP4+), 5,10-di(4-methylphenyl)-15,20-di(4-N,N,N-trimethylammoniumphenyl)porphyrin (MPAP2+) and 5,10,15,20-tetra(4-sulphonatophenyl)porphyrin (TPPS4-) were examined under different conditions. These porphyrins were rapidly bound to E. coli cells (<2.5min) and the uptake of photosensitizers was not dependent on incubation temperature, reaching values of 0.61, 0.18 and 0.08nmol/108 cells for TMAP4+, MPAP2+ and TPPS4-, respectively. The addition of Ca2+ or Mg2+ to the cultures enhanced the uptake of MPAP2+ and TPPS4- by cells. In contrast, the amount of TMAP4+ bound to cells was decreased. The presence of EDTA produced an increase in the uptake of porphyrins by cells, while CS mainly enhanced the amount of TPPS4- bound to E. coli. The photoinactivation of E. coli cells mediated by TMAP4+ was highly effective even at low concentration (1μM) and short irradiation period (5min). However, a reduction in the phototoxicity was found for TMAP4+ in presence of Ca2+ and Mg2+. In contrast, the phototoxic activity mediated by MPAP2+ and TPPS4- was increased. Addition of EDTA did not show effect on the photoinactivation induced by cationic porphyrins, while a small enhance was found for TPPS4-. Moreover, inactivation of E. coli cells was achieved in the presence CS. This cationic polymer was antimicrobial by itself in the dark. Using a slightly toxic CS concentration, the phototoxic activity induced by TMAP4+ was diminished. This effect was mainly observed at lower concentration of TMAP4+ (0.5-1μM). In contrast, an increase in E. coli photoinactivation was obtained for MPAP2+ and TPPS4- in presence of CS. Thus, this natural polymeric destabilizer agent mainly benefited the photoinactivation mediated by TPPS4-.Fil: Gsponer, Natalia Soledad. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; ArgentinaFil: Spesia, Mariana Belen. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; ArgentinaFil: Durantini, Edgardo Néstor. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentin

Porphyrins containing basic aliphatic amino groups as potential broad-spectrum antimicrobial agents

New porphyrin derivatives bearing basic aliphatic amino groups were synthesized from the condensation of meso-4-[(3-N,N-dimethylaminopropoxy)phenyl]dipyrromethane, pentafluorobenzaldehyde and 4-(3-N,N-dimethylaminopropoxy)benzaldehyde. The reaction was catalyzed by trifluoroacetic acid in acetonitrile. This approach was used to obtain porphyrins with different patterns of substitution, of which three of them were isolated: 5,15-di(4-pentafluorophenyl)-10,20-di[4-(3-N,N-dimethylaminopropoxy)phenyl]porphyrin (F10APP), 5-(4-pentafluorophenyl)-10,15,20-tris[4-(3-N,N-dimethylaminopropoxy)phenyl]porphyrin (F5APP) and 5,10,15,20-tetrakis[4-(3-N,N-dimethylaminopropoxy)phenyl]porphyrin (TAPP). The UV–vis spectroscopic characterizations and the photodynamic effect of these compounds were compared in N,N-dimethylformamide. These porphyrins showed red fluorescence emission with quantum yields of 0.09-0.15. Moreover, they sensitized the production of singlet molecular oxygen, reaching quantum yields values of 0.33-0.53. Photodynamic inactivation was studied in two bacteria, Staphylococcus aureus and Escherichia coli, and a yeast Candida albicans. High amount of cell-bound porphyrin was obtained at short times (<2 min) of incubation. After 15 min irradiation, a 7 log reduction of S. aureus was found for cells treated with 1 μM F5APP. Similar photokilling was obtained in E. coli, but using 7.5 μM F5APP and 30 min irradiation. Under these conditions, a decrease of 5 log was observed in C. albicans cells. An increase in cell survival was observed by addition of sodium azide, whereas a slight protective effect was found in the presence of D-mannitol. Moreover, the photoinactivation mediated by these porphyrins was higher in D2O than in water. Thus, these porphyrins induced the photodynamic activity mainly through the intermediacy of O2(1Δg). In particular, F5APP was a highly effective photosensitizer with application as a broad-spectrum antimicrobial. This porphyrin contains three basic aliphatic amino groups that may be protonated at physiological pH. In addition, it is substituted by a lipophilic pentafluorophenyl group, which confers an amphiphilic character to the tetrapyrrolic macrocycle. This effect can increase the interaction with the cell envelopment, improving the photocytotoxic activity against the microorganisms.Fil: Scanone, Ana Coral. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Gsponer, Natalia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; ArgentinaFil: Alvarez, María Gabriela. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Durantini, Edgardo Néstor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentin

Photodynamic properties and photoinactivation of microorganisms mediated by 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin covalently linked to silica-coated magnetite nanoparticles

Magnetic nanoparticles of Fe3O4 (MNP) were synthesized by co-precipitating Fe2+ and Fe3+ ions in an ammonia solution. This MNP was coated with silica using sodium metasilicate to obtain silica-coated MNP (MNPSi). Grafting of aminopropyl groups on MNP or MNPSi was performed with (3-aminopropyl)trimethoxysilane to form MNPNH2 or MNPSiNH2, respectively. 5,10,15,20-Tetrakis(4-carboxyphenyl)porphyrin (TCPP) was covalently bound onto the MNPNH2 or MNPSiNH2 via carbodiimide activation to obtain MNPNH-TPCC or MNPNH-TPCC, respectively. These MNP presented an average diameter of about 15 nm. UV–vis absorption spectra presented the characteristic Soret and Q bands of TCPP covalently linked to the nanoparticles. The MNP containing TCPP produced a high photodecomposition of 2,2-(anthracene-9,10-diyl)bis(methylmalonate), which was used to detect singlet molecular oxygen O2(1Δg) production in water. Moreover, these nanoparticles sensitized the photooxidation of L-tryptophan in water, mainly mediated by a type II photoprocess. Photoinactivation of microorganisms was investigated in Staphylococcus aureus, Escherichia coli and Candida albicans. In vitro experiments showed that photosensitized inactivation induced by MNPSiNH-TCPP improved with an increase of irradiation times. After 30 min irradiation, a 2.5 log reduction was found for S. aureus and C. albicans. Also, the last conditions produced a decrease of 3 log in E. coli. Similar result was obtained MNPNH-TCPP. However, the main difference between these nanoparticles as photosensitizer was found after recycling experiments. While the photoinactivation mediated by MNPNH-TCPP rapidly decrease after one cycle, MNPSiNH-TCPP was still efficient after three cycles of inactivation. Therefore, MNPSiNH-TCPP is an interesting and versatile photodynamic active material to eradicate microorganisms.Fil: Scanone, Ana Coral. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Gsponer, Natalia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; ArgentinaFil: Alvarez, María Gabriela. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Durantini, Edgardo Néstor. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentin

Approaches to unravel pathways of reactive oxygen species in the photoinactivation of bacteria induced by a dicationic fulleropyrrolidinium derivative

The photodynamic mechanism sensitized by N,N-dimethyl-2-[4-(3-N,N,N-trimethylammoniopropoxy)phenyl]fulleropyrrolidinium (DPC602+) was investigated in Staphylococcus aureus cells. Different experimental conditions were used to detect reactive oxygen species (ROS) in S. aureus cell suspensions. First, a photoinactivation of 4 log decrease of S. aureus viability was chosen using 0.5 μM DPC602+ and 15 min irradiation. An anoxic atmosphere indicated that oxygen was required for an effective photoinactivation. Also, photoprotection was found in the presence of sodium azide, whereas the photocytotoxicity induced by DPC602+ increased in D2O. The addition of diazabicyclo[2.2.2]octane or D-mannitol produced a reduction in the S. aureus photokilling. Moreover, singlet molecular oxygen, O2(1Δg), was detected by the reaction with 9,10-dimethylanthracene into the S. aureus cells. A decrease in the photoinactivation of S. aureus was observed in the presence of β–nicotinamide adenine dinucleotide reduced form, which was dependent on the NADH concentration. Therefore, under aerobic condition the photocytotoxicity activity induced by DPC602+ was mediated by mainly a contribution of type II process. Moreover, photoinactivation of S. aureus was possible with DPC602+ in the presence of azide anions under anoxic condition. However, these conditions were not effective to photoinactivate Escherichia coli. On the other hand, the addition of potassium iodide produced an increase in the photokilling of bacteria, depending on the KI concentration and irradiation times. The formation of reactive iodine species may be contributing to inactivate S. aureus cells photoinduced by DPC602+.Fil: Gsponer, Natalia Soledad. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Agazzi, Maximiliano Luis. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Spesia, Mariana Belen. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Durantini, Edgardo Néstor. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentin

Synthesis, spectroscopic properties and photodynamic activity of a fulleropyrrolidine bearing a basic amino group and its dicationic analog against Staphylococcus aureus

N-Methyl-2-[4-(3-N,N-dimethylaminopropoxy)phenyl]fulleropyrrolidine (MPC60) was synthesized by 1,3-dipolar cycloaddition reaction of 4-(3-N,N-dimethylaminopropoxy)benzaldehyde, N-methylglycine and fullerene C60 in 43% yield. The amine groups of MPC60 were methylated with dimethyl sulfate to obtain a dicationic fullerene DPC602+ in 96 % yield. Absorption spectra of these fullerenes in N,N-dimethylformamide (DMF) and toluene/sodium bis(2-ethylhexyl) sulfosuccinate (AOT)/water reverse micelles showed strong absorptions in the UV region, with a peak at 430 nm and broader range of absorption up to 710 nm. Fluorescence quantum yields of about 10-4 were calculated for these compounds in DMF. A higher singlet molecular oxygen, O2(1Δg), generation was found for MPC60 than DPC602+ in DMF. The photodynamic activity of these photosensitizers remained high in a simple biomimetic AOT system. Also, the formation of superoxide anion radical induced by MPC60 and DPC602+ was detected in presence of NADH. Decomposition of l-tryptophan in DMF mediated by both fullerenes indicated a possible contribution of type I photoprocess. Photosensitized inactivation of Staphylococcus aureus was investigated using different conditions. Cell suspensions of 108 cells/mL incubated with 0.5 μM fullerene and irradiated for 30 min exhibited a 4.4 and 5.0 log decrease of cell survival by MPC60 and DPC602+, respectively. Therefore, these fullerene derivatives can be used as effective photosensitizers for the photodynamic inactivation of S. aureus cells.Fil: Agazzi, Maximiliano Luis. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Spesia, Mariana Belen. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Gsponer, Natalia Soledad. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Milanesio, María Elisa. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Durantini, Edgardo Néstor. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentin

Light-harvesting antenna and proton-activated photodynamic effect of a novel BODIPY-fullerene C60 dyad as potential antimicrobial agent

A covalently linked BODIPY−fullerene C 60 dyad (BDP−C 60 ) was synthesized as a two-segment structure, which consists of a visible light-harvesting antenna attached to an energy or electron acceptor moiety. This structure was designed to improve the photodynamic action of fullerene C 60 to inactivate bacteria. The absorption spectrum of BDP−C 60 was found to be a superposition of the spectra of its constitutional moieties, whereas the fluorescence emission of the BODIPY unit was strongly quenched by the fullerene C 60 . Spectroscopic, calculations, and redox studies indicate a competence between photoinduced energy and electron transfer. Protonating the dimethylaminophenyl substituent through addition of an acidic medium led to a substantial increase in the fluorescence emission, triplet excited state formation, and singlet molecular oxygen production. At physiological pH, photosensitized inactivation of Staphylococcus aureus mediated by 1 μM BDP−C 60 exhibited a 4.5 log decrease of cell survival (>99.997 %) after 15 min irradiation. A similar result was obtained with Escherichia coli using 30 min irradiation. Moreover, proton-activated photodynamic action of BDP−C 60 turned this dyad into a highly effective photosensitizer to eradicate E. coli. Therefore, BDP−C 60 is an interesting photosensitizing structure in which the light-harvesting antenna effect of the BODIPY unit combined with the protonation of dimethylaminophenyl group can be used to improve the photoinactivation of bacteria.Fil: Agazzi, Maximiliano Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaFil: Durantini, Javier Esteban. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados; ArgentinaFil: Gsponer, Natalia Soledad. Universidad Nacional de Río Cuarto. Instituto para el Desarrollo Agroindustrial y de la Salud. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto para el Desarrollo Agroindustrial y de la Salud; ArgentinaFil: Durantini, Andres Matías. Universidad Nacional de Río Cuarto. Instituto para el Desarrollo Agroindustrial y de la Salud. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto para el Desarrollo Agroindustrial y de la Salud; ArgentinaFil: Bertolotti, Sonia Graciela. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Durantini, Edgardo Néstor. Universidad Nacional de Río Cuarto; Argentina. Universidad Nacional de Río Cuarto. Instituto para el Desarrollo Agroindustrial y de la Salud. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto para el Desarrollo Agroindustrial y de la Salud; Argentin

Experimental and theoretical studies on the enantioselectivity of molecularly imprinted polymers prepared with a chiral functional monomer

A comprehensive study on the enantioseparation of racemic bis[1-phenylethyl]amine (PEA) on a series of molecularly imprinted polymers (MIPs) prepared using the chiral functional monomer (S)-2-(2-methyl-acryloylamino)-3-phenyl propionic acid (MAPP) is reported. MIP-R, MIP-S and MIP-RS, were synthesized separately by imprinting the pure enantiomers (R-, S-PEA) and racemic PEA, respectively, MAPP, EDGMA as crosslinker and chloroform as the porogen. It was found that all MIPs prepared were able to resolve the PEA racemate. Residence times (tr) and enantioselectivity factors (α) were estimated from typical elution chromatography experiments. Frontal chromatography experiments were conducted to acquire the adsorption isotherms for both enantiomers on the different MIPs (and on the non-imprinted polymer, NIP). The adsorption isotherms were analyzed using the affinity spectrum (AS) and the expectation-maximization (EM) methods. The study also involved the theoretical evaluation of the MAPP/enantiomers interactions in the pre-polymer mixture. The EM method predicts mono- and bimodal distribution of affinity binding sites depending upon the polymer analyzed. Apparently, the enantioseparation process depends on relatively small differences in the stabilization of the diasteroisomeric ion-pairs PEA/MAPP complexes on the surface of the polymers.Fil: Torres, Juan Jose. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Gsponer, Natalia Soledad. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Ramirez, Cristina Lujan. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Vera, Domingo Mariano Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Montejano, Hernan Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; ArgentinaFil: Chesta, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentin