A journal in ascendancy

Dear authors, reviewers and readers. We are delighted to report on another exciting and productive year for Methods and Applications in Fluorescence (MAF). Although only in its 3rd year the journal already seems to be living up to its promise of becoming the highest quality journal in the field

Fluorescent carbon dioxide indicators

Over the last decade, fluorescence has become the dominant tool in biotechnology and medical imaging. These exciting advances have been underpinned by the advances in time-resolved techniques and instrumentation, probe design, chemical / biochemical sensing, coupled with our furthered knowledge in biology. Complementary volumes 9 and 10, Advanced Concepts of Fluorescence Sensing: Small Molecule Sensing and Advanced Concepts of Fluorescence Sensing: Macromolecular Sensing, aim to summarize the current state of the art in fluorescent sensing. For this reason, Drs. Geddes and Lakowicz have invited chapters, encompassing a broad range of fluorescence sensing techniques. Some chapters deal with small molecule sensors, such as for anions, cations, and CO2, while others summarize recent advances in protein-based and macromolecular sensors. The Editors have, however, not included DNA or RNA based sensing in this volume, as this were reviewed in Volume 7 and is to be the subject of a more detailed volume in the near future

Dialysis-assisted fiber optic spectroscopy for in situ biomedical sensing

A miniature fiber optic spectrometer enclosed within a semipermeable (dialysis) membrane is proposed for in vivo interstitial sensing applications. The semipermeable membrane acts as a molecular filter, allowing only small molecules to pass through to the sampling volume. This filtering, in principle, should enable continuous in vivo drug sensing, removing the necessity for complex microdialysis systems. We use a biological phantom to examine the reliable detection of a fluorescence signal from small dye molecules in the presence of large fluorophores and scatterers. We find that spectral artefacts arising from scatterers and large fluorophores are substantially suppressed, simplifying the spectral analysis. In addition, the measured sampling rate of 157 s is superior to existing in vivo tissue assaying techniques such as microdialysis, which can take tens of minutes. (c) 2006 Society of Photo- Optical Instrumentation Engineers

Synthesis of new tacrine analogues from 4-amino-1H-pyrrole-3-carbonitrile

An easy preparation of 4-aminopyrrole-3-carbonitrile derivatives, and their transformation into new substituted pyrrolo[3,2-b]pyridines is described, in one step, via Friedländer reaction under microwave irradiation and classical heating methods. The use of microwave irradiation led to high conversion and shorter times.Fundação para a Ciência e a Tecnologia (FCT) - NMR Network, REEQ/ 630/QUI/2005, SFRH/BPD/31490/2006Fundo Europeu de Desenvolvimento Regional (FEDER

Optoelectronic Capillary Sensors in Microfluidic and Point-of-Care Instrumentation

This paper presents a review, based on the published literature and on the authors’ own research, of the current state of the art of fiber-optic capillary sensors and related instrumentation as well as their applications, with special emphasis on point-of-care chemical and biochemical sensors, systematizing the various types of sensors from the point of view of the principles of their construction and operation. Unlike classical fiber-optic sensors which rely on changes in light propagation inside the fiber as affected by outside conditions, optical capillary sensors rely on changes of light transmission in capillaries filled with the analyzed liquid, which opens the possibility of interesting new applications, while raising specific issues relating to the construction, materials and instrumentation of those sensors

Building a quality home for fluorescence

With the announcement of our first impact factor of 2.429, and the recent news that Methods and Applications in Fluorescence (MAF) will be indexed by MEDLINE and searchable from the PubMed® database, this year has been a very exciting year for the journal. After only a few years, MAF is already establishing itself as the home of the highest quality fluorescence research. Our desire has been for a journal in our area which could showcase the best work in fluorescence and so give a fitting home for what is a truly multi-disciplinary field, combining cutting edge optical and imaging techniques with organic and bio-chemistry to address major issues in biology and medicine

Hypoxia in Leishmania major Skin Lesions Impairs the NO-Dependent Leishmanicidal Activity of Macrophages

Cure of infections with Leishmania major is critically dependent on the ability of macrophages to induce the type 2 nitic oxide (NO) synthase (NOS2) that produces high levels of NO in the presence of ample oxygen. Therefore, we analyzed the oxygen levels found in leishmanial skin lesions and their effect on the NOS2-dependent leishmanicidal activity of macrophages (MΦ). When L. major skin lesions of self-healing C57BL/6 mice reached their maximum size, the infected tissue displayed low oxygen levels (pO2~21Torr). MΦ activated under these oxygen tensions failed to produce sufficient amounts of NO to clear L. major. Nos2-deficient and hypoxic wild-type macrophages displayed a similar phenotype. Killing was restored when MΦ were reoxygenated or exposed to a NO donor. The resolution of the lesion in C57BL/6 mice was paralleled by an increase of lesional pO2. When mice were kept under normobaric hypoxia, this caused a persistent suppression of the lesional pO2 and a concurrent increase of the parasite load. In Nos2-deficient mice, there was no effect of atmospheric hypoxia. Low oxygen levels found at leishmanial skin lesions impaired the NOS2-dependent leishmanicidal activity of MΦ. Hence, tissue oxygenation represents an underestimated local milieu factor that participates in the persistence of Leishmania

Microtiter plate assay for phosphate using a europium–tetracycline complex as a sensitive luminescent probe

A new luminescent europium probe is presented for the determination of phosphate (P) in microtiter plate format. The assay is based on the quenching of the luminescence of the europium–tetracycline (EuTc) 1:1 complex by phosphate using a reagent concentration of 20.8 μmol/L. The probe is excited at 400 nm and displays a large Stokes’ shift of 210 nm. The emission maximum is located at 616 nm. The system works best at neutral pH 7 and is therefore suitable for phosphate determination in biological and biochemical systems. The linear range of the calibration plot is from 5 × 10−6 mol/L to 7.5 × 10−4 mol/L of phosphate, and the limit of detection is 3 μmol/L

Anion-lnduced Fluorescence Quenching of a New Zwitterionic Biacridine Derivative

The effect of halides and different buffer anions on the quenching of the fluorescence of the new probe 10,10′-bis(3-sulfopropyl)-9,9′-biacridine (SPBA) has been studied using fluorescence and decay time measurements. The linearity of the Stern-Volmer plot indicates that fluorescence quenching by halides can be described reasonably well by a single-exponential decay with a K of 4.06 times 10⁶M⁻¹s⁻¹for chloride, 7.83 times 10⁶M⁻¹s⁻¹for bromide and 1.12 times 10⁷M⁻¹s⁻¹for iodide. We have found that SPBA is collisionally quenched also by the buffers 3-(N-mor-pholino)propanesulfonic acid (MOPS) and N-2-hydroxy-ethylpiperazine-N′-ethansulfonic acid (HEPES). The bi-molecular rate constants are 1.67 × 10⁶M⁻¹s⁻¹for HEPES and 1.44 times 10⁶M⁻¹s⁻¹for MOPS