Spatial and temporal control of molecular mechanisms can be achieved using photolabile bonds that connect biomolecules to protective caging groups, which can be cleaved upon irradiation of a specific wavelength, releasing the biomolecule ready-to-use. Here we apply and improve a previously reported strategy to tightly control in vitro transcription reactions. The strategy involves two caging molecules that block both ATP and GTP nucleotides. Additionally, we designed a molecular beacon complementary to the synthesized mRNA to infer its presence through a light signal. Upon release of both nucleotides through a specific monochromatic light (390 and 325 nm) we attain a light signal indicative of a successful in vitro transcription reaction. Similarly, in the absence of irradiation, no intense fluorescence signal was obtained. We believe this strategy could further be applied to DNA synthesis or the development of logic gates.

Magnetic core coatings modify the efficiency of nanoparticles used as contrast agents for MRI. In studies of these phenomena, care should be given to take into account possible effects of the specific micro-environment where coated nanoparticles are embedded. In the present work, the longitudinal and transverse relaxivities of superparamagnetic iron oxide nanoparticles stabilized with short-chain polyethylene glycol molecules (PEGylated SPIONs) were measured in a 7T magnetic field. PEGylated SPIONs with two different diameters (5 and 10nm) were studied. Two different PEGylated magnetoliposomes having liposome bilayer membranes composed of egg-phosphatidylcholine, cholesterol and 1,2-distearoyl-sn-glycerol-3-phosphoethanolamine-N-[methoxy PEG-2000] were also studied for their relaxivities, after being loaded with the PEGylated SPION of 5 or 10nm. This type of liposomes is known to have long residence time in bloodstream that leads to an attractive option for therapeutic applications. The influence of the magnetic core coating on the efficiency of the nanosystem as a negative contrast agent for MRI was then compared to the cumulative effect of the coating plus the specific micro-environment components. As a result, it was found that the PEGylated magnetoliposomes present a 4-fold higher efficiency as negative contrast agents for MRI than the PEGylated SPION.

Cancer development is amultistep process in which exosomes play important roles. Exosomes are small vesicles formed in vesicular bodies in the endosomal network. The major role of exosomes seems to be the transport of bioactive molecules between cells. Depending on the cell of origin, exosomes are implicated in the regulation of several cellular events, with phenotypic consequences in recipient cells. Cancer derived exosomes (CCEs) are important players in the formation of the tumour microenvironment by (i) enabling the escape of tumour cells to immunological system and help initiating the inflammatory response; (ii) acting in the differentiation of fibroblasts and mesenchymal cells into myofibroblasts; (iii) triggering the angiogenic process; and (iv) enhancing the metastatic evolution of the tumour by promoting epithelial to mesenchymal transformation of tumour cells and by preparing the tumour niche in the new anatomical location. Since the finding that exosomes content resembles that of the cell of origin, they may be regarded as suitable biomarkers for cancer diagnosis, allowing for diagnosis and prognosis via a minimal invasive procedure. Exosome involvement in cancer may open new avenues regarding therapeutics, such as vectors for targeted drug delivery.

This chapter focuses on several sensing strategies and major recent advances in the use of gold nanoparticles in (bio)sensing of chemical and biological analytes. A brief introduction is presented on relevant properties of gold nanoparticles for sensing, the main types of (bio)chemical sensors, and the main detection techniques, followed by subsections according to sensing methodologies. These include colorimetric sensing and the biobarcode assay, fluorometric-based methods, electric and electrochemical sensing, and, last, more recent and advanced methodologies such as surface plasmon resonance and Raman-based sensors. In closing, relevance is given to advanced methods, featuring extremely high sensitivity and selectivity, down to single-molecule detection. Anisotropic gold nanoparticles have a special role in future developments.

The lipoxygenase (LOX) products have been identified as mediators of a series of inflammatory diseases, namely rheumatoid arthritis, inflammatory bowel disease, psoriasis, allergic rhinitis, atherosclerosis and certain types of cancer. Hence, LOX inhibitors are of interest for the modulation of these phenomena and resolution of the inflammatory processes. During LOX activity, peroxyl radical complexes are part of the reaction and may function as sources of free radicals. Thus antioxidants, such as flavonoids, capable of inhibiting lipid peroxidation and scavenging free radicals, may act as LOX inhibitors. The aim of this work was to assess the structure–activity relationship among a series of flavonoids concerning 5-LOX inhibition, through a systematic study of the inhibition of the formation of LTB4 in human neutrophils. The type of inhibition of the flavonoids was further studied using soybean LOX, type I, and Saturation Transfer Difference 1H NMR (STD-1H NMR) was used to characterize the binding epitopes of the compounds to LOX-1. The obtained results reinforce flavonoids as effective inhibitors of LTB4 production in human neutrophils. It was also possible to establish a structure/activity relationship for the inhibitory activity and the type of inhibition.

The production of ultra-low-sulfur diesel is an important worldwide demand. In this work a novel integrated method for desulfurization of diesel is proposed based on the combination of Bronsted acid catalyzed oxidation and the selective removal of the oxidized products using a molecularly imprinted polymer (MIP) produced in supercritical carbon dioxide (scCO2). The biphasic oxidation reaction of dibenzothiophene sulfone (DBT){,} as model substrate{,} and H2O2 as oxidant{,} was optimized by testing different acid catalysts{,} and also different phase transfer catalysts (PTC){,} including two different ionic liquids (ILs) trihexyl(tetradecyl)phosphoniumchloride [P6{,}6{,}6{,}14]Cl and Aliquat[registered sign]. The products of the efficient oxidation of DBT{,} dibenzothiophene sulfoxide (DBTSO) and dibenzothiophene sulfone (DBTSO2){,} were then selectively removed from real diesel using the MIP.

This study was developed with the purpose to investigate the effect of polysaccharide/plasticiser concentration on the microstructure and molecular dynamics of polymeric film systems, using transmission electron microscope imaging (TEM) and nuclear magnetic resonance (NMR) techniques. Experiments were carried out in chitosan/glycerol films prepared with solutions of different composition. The films obtained after drying and equilibration were characterised in terms of composition, thickness and water activity. Results show that glycerol quantities used in film forming solutions were responsible for films composition; while polymer/total plasticiser ratio in the solution determined the thickness (and thus structure) of the films. These results were confirmed by TEM. NMR allowed understanding the films molecular rearrangement. Two different behaviours for the two components analysed, water and glycerol were observed: the first is predominantly moving free in the matrix, while glycerol is mainly bounded to the chitosan chain.

Abstract The knowledge on the binding of vanadium ions and complexes to serum proteins and how vanadium might be transported in blood and up-taken by cells has received much attention during the last decade, particularly as far as the transport of VIVO2+ is concerned. In this work we revise and discuss some relevant aspects of previous research, namely the two main types of binding proposed for transport of VIVO(carrier)2 complexes. New results, obtained by circular dichroism (CD), \{EPR\} and gel electrophoresis, regarding the binding of vanadium to hTF in the oxidation states +5 and +3 are also presented. Namely, evidences for the binding of VV-species to diferric-transferrin, designated by (FeIII)2hTF, as well as to (AlIII)2hTF, are presented and discussed, the possibility of up-take of vanadate by cells through (FeIII)2hTF endocytosis being suggested. It is also confirmed that \{VIII\} binds strongly to hTF, forming di-vanadium(III)-transferrin, designated by (VIII)2hTF, and gel electrophoresis experiments indicate that (VIII)2hTF corresponds to a ‘closed conformation’ similar to (FeIII)2hTF.

New long circulating magnetoliposomes coated with polyethylene glycol (PEG), and loaded with PEG-coated 10nm superparamagnetic iron oxide nanoparticles (SPION), were developed. The magnetoliposomes relaxivities r1, r2 measured in a magnetic field of 7 T showed a minor effect on T1, but a major effect on T2. These nanosystems were used as a negative contrast agent for MRI in a nonclinical study to visualize, in a rat model of liver ischemia, ischemia-reperfusion injuries. Magnetic resonance micro-images (MRM) at 7 T were obtained for rat liver with and without magnetoliposomes administration and analyzed in comparison with liver biomarkers and histological results. These new long circulating magnetoliposomes enhanced the detection of lesions indicating their potential use as efficient MRI negative contrast agent for the detection of liver ischemia-reperfusion injuries. FROM THE CLINICAL EDITOR: This paper describes the generation of PEGylated magnetoliposomes and demonstrates their feasibility as negative contrast agents in a liver ischemia-reperfusion rat model.

A novel method to prepare silica nano-sized particles incorporating polyoxometalates was developed leading to a new efficient heterogeneous oxidative catalyst. Zinc-substituted polyoxotungstate [PW11Zn(H2O)O39](5-) (PW11Zn) was encapsulated into silica nanoparticles using a cross-linked organic-inorganic core, performed through successive spontaneous reactions in water. The potassium salt of PW11Zn and the composite formed, PW11Zn-APTES@SiO2, were characterized by a myriad of solid-state methods such as FT-IR, FT-Raman, (31)P and (13)C CP/MAS solid-state NMR, elemental analysis and SEM-EDS, confirming the integrity of the PW11Zn structure immobilized in the silica nanoparticles. The new composite has shown to be a versatile catalyst for the oxidation of olefins and also to catalyze the desulfurization of a model oil using H2O2 as the oxidant and acetonitrile as the solvent. The novel composite material was capable of being recycled without significant loss of activity and maintaining its structural stability for consecutive desulfurization and olefin oxidative cycles.