Serum albumins are efficient delivery systems for the photosensitizer hypericin in photosensitization-based treatments against Staphylococcus aureus

The naturally occurring photosensitizer hypericin can be effectively delivered to bacterial cells using serum albumins as biocompatible carriers. Using a combination of spectroscopic methods we demonstrate that the photophysics of hypericin is fully preserved when bound to these proteins. Thanks to the excellent transport capabilities of serum albumins, that deliver hypericin to Gram-positive S. aureus, an efficient antibacterial action was observed, with a reduction of up to 8 log in the number of colony-forming units. The photoactive material is fully compatible with the use in food processing environments, and may be exploited as a viable method for decontamination from S. aureus and other Gram-positive bacteria

How promising is phototherapy for cancer?

Oncological phototherapy, including current photodynamic therapy (PDT), developmental photoactivated chemotherapy (PACT) and photothermal therapy (PTT), shows promising photo-efficacy for superficial and internal tumours. The dual application of light and photochemotherapeutic agents allows accurate cancer targeting, low invasiveness and novel mechanisms of action. Current advances in new light sources and photoactive agents are encouraging for future development

Novel combinations of experimental and computational analysis tested on the binding of metalloprotoporphyrins to albumin

Accepted author manuscriptThe evidence that Human Serum Albumin (HSA) binds metal ions and organometallic compounds has generated interest in its physiological role as a metalloprotein and as a vehicle for synthetic biology applications (e.g., synthetic blood and solar energy conversion). HSA has been shown to bind metallo-porphyrins, however, the structural details of such interactions are available only for the HSA:heme complex. A typical challenge for studying the interaction of proteins with metalloporphyrins is the poor solubility of the ligands that affect the characterization the complexes. The manuscript shows that a combination of dialysis and centrifugation yields aqueous solutions that contain >90% HSA:porphyrin complexes and virtually eliminate aggregated ligands. The removal of aggregates increases the quality of the optical spectroscopy data which, in turn, yield more accurate binding constants (~0.1 and 2.1 × 106 M−1) and reveal FRET between Trp214 and the porphyrins. The Trp-porphyrin distance was estimated to be within the 28–34 Å range and was used to guide the search of binding sites through a novel feedback approach with docking simulations. Results suggest while some protoporphyrins (metal-free, Fe(III)PPIX and Mg(II)PPIX) bind HSA at the heme site, others (Zn(II)PPIX, Mn(III)PPIX and Sn(IV)PPIX) are more likely to bind the Cys34.Ye

Synthesis, characterisation and photochemistry of PtIV pyridyl azido acetato complexes

PtII azido complexes [Pt(bpy)(N3)2] (1), [Pt(phen)(N3)2] (2) and trans-[Pt(N3)2(py)2] (3) incorporating the bidentate diimine ligands 2,2′-bipyridine (bpy), 1,10-phenanthroline (phen) or the monodentate pyridine (py) respectively, have been synthesised from their chlorido precursors and characterised by X-ray crystallography; complex 3 shows significant deviation from square-planar geometry (N3–Pt–N3 angle 146.7°) as a result of steric congestion at the Pt centre. The novel PtIV complexes trans, cis-[Pt(bpy)(OAc)2(N3)2] (4), trans, cis-[Pt(phen)(OAc)2(N3)2] (5), trans, trans, trans-[Pt(OAc)2(N3)2(py)2] (6), were obtained from 1–3via oxidation with H2O2 in acetic acid followed by reaction of the intermediate with acetic anhydride. Complexes 4–6 exhibit interesting structural and photochemical properties that were studied by X-ray, NMR and UV-vis spectroscopy and TD-DFT (time-dependent density functional theory). These PtIV complexes exhibit greater absorption at longer wavelengths (ε = 9756 M−1 cm−1 at 315 nm for 4; ε = 796 M−1 cm−1 at 352 nm for 5; ε = 16900 M−1 cm−1 at 307 nm for 6, in aqueous solution) than previously reported PtIV azide complexes, due to the presence of aromatic amines, and 4–6 undergo photoactivation with both UVA (365 nm) and visible green light (514 nm). The UV-vis spectra of complexes 4–6 were calculated using TD-DFT; the nature of the transitions contributing to the UV-vis bands provide insight into the mechanism of production of the observed photoproducts. The UV-vis spectra of 1–3 were also simulated by computational methods and comparison between PtII and PtIV electronic and structural properties allowed further elucidation of the photochemistry of 4–6

Photoactivated chemotherapy (PACT) : the potential of excited-state d-block metals in medicine

The fields of phototherapy and of inorganic chemotherapy both have long histories. Inorganic photoactivated chemotherapy (PACT) offers both temporal and spatial control over drug activation and has remarkable potential for the treatment of cancer. Following photoexcitation, a number of different decay pathways (both photophysical and photochemical) are available to a metal complex. These pathways can result in radiative energy release, loss of ligands or transfer of energy to another species, such as triplet oxygen. We discuss the features which need to be considered when developing a metal-based anticancer drug, and the common mechanisms by which the current complexes are believed to operate. We then provide a comprehensive overview of PACT developments for complexes of the different d-block metals for the treatment of cancer, detailing the more established areas concerning Ti, V, Cr, Mn, Re, Fe, Ru, Os, Co, Rh, Pt, and Cu and also highlighting areas where there is potential for greater exploration. Nanoparticles (Ag, Au) and quantum dots (Cd) are also discussed for their photothermal destructive potential. We also discuss the potential held in particular by mixed-metal systems and Ru complexes

Qualidade óssea de ratas wistar em crescimento alimentadas com ração hiperlipídica

A relação entre a obesidade e o tecido ósseopermanece contraditória, mesmo após anos deinvestigações. Os resultados são inespecíficos,sobretudo, quando é avaliado o efeito de dietas ricas emgordura em modelos experimentais. O objetivo desseestudo foi avaliar a qualidade óssea de ratas wistar emcrescimento alimentadas com ração hiperlipídica. Foramutilizadas 20 ratas pós-desmame. Elas foram divididasigualmente em dois grupos, sendo PAD: ratasalimentadas com ração padrão AIN-93 e HIP: ratasalimentadas com ração AIN-93 modificada de modo aconter 60% da energia em forma de gordura. O períodode tratamento foi de 5 semanas. As ratas foramsubmetidas à eutanásia por doses excessivas deanestesia e, após necropsia e dissecação, as tíbias foramanalisadas quando à Densidade Mineral Óssea (DMO),Resistência Mecânica e Análise microestrutural atravésda Microscopia Eletrônica de Varredura. A DMO foiestatisticamente maior no grupo HIP em relação aogrupo PAD, entretanto, a resistência mecânica foiestatisticamente igual entre os dois grupos. Amicroarquitetura permaneceu similar entre os doisgrupos após análise quantitativa. Foi possível concluir,portanto, que embora a DMO tenha sido maior no grupoalimentado com ração hiperlipídica, a resistênciamecânica e microarquitetura óssea permaneceu intactaapós 5 semanas de tratamento.The relationship between obesity and bonetissue remains contradictory, even after years ofinvestigation. The results are non-specific, particularlywhen it assessed the effect of high-fat diets inexperimental models. The aim of this study was toevaluate bone quality of wistar growing rats fed withhigh-fat diet. 20 post-weaning wistars rats were used inthis study. They were equally divided into two groups,PAD: rats fed with standard diet AIN-93 and HIP: ratsfed with a modified AIN-93 diet to contain 60% ofenergy as fat. The exposure period was 5 weeks. Therats were euthanized by overdose of anesthesia and,after autopsy and dissection, tibiae were analyzed whenthe Bone Mineral Density, Mechanical Strength andMicrostructural Analysis by Scanning ElectronMicroscopy. BMD was statistically higher in the HIPgroup compared to the PAD group. However, themechanical strength was statistically similar betweenthe two groups. Microarchitecture remained similarbetween the two groups observed by quantitativeanalysis. It was concluded, therefore, that althoughBMD was higher in the group fed high-fat diet, themechanical strength and bone microarchitectureremained intact after 5 weeks of exposure

Wayforlight : the Catalogue of European light sources

Wayforlight.eu is the gateway to find-ing the most suitable instruments for experiments with synchrotron, FEL, and laser light sources. The portal's main asset is a de-tailed searchable catalogue of facilities, beam-lines, and instrumentation available at Euro-pean light sources. Thanks to its advanced search tools, a visitor can filter beamlines by scientific discipline, by technique, but also by energy range or sample type

Aminoacidi aromatici come probes intrinseci di macromolecole biologiche: rilassamenti termici e variazioni volumetriche fotoindotte in molecole contenenti un singolo triptofano

Dottorato di ricerca in fisica. 7. ciclo. A.a. 1994-95Consiglio Nazionale delle Ricerche - Biblioteca Centrale - P.le Aldo Moro, 7, Rome; Biblioteca Nazionale Centrale - P.za Cavalleggeri, 1, Florence / CNR - Consiglio Nazionale delle RichercheSIGLEITItal