Preparation of metal nanoparticles by femtosecond laser ablation

Nanoparticles (NPs) proved to have numerous applications in various fields, including biomedicine and environmental sciences. In this work, we designed and created an apparatus for fabrication of metal NPs directly in liquids initiated by femtosecond laser pulses. The laser parameters leading to ~10 μJ/pulse energy and 0.1 GW peak power resulted in predominantly spherical particles with the sizes varying from <10 nm to ~100 nm in diameter. NPs generated from Cobalt and Zinc targets were smaller in order of magnitude compared to that of Nickel. The fabricated NPs were characterized by scanning electron microscopy, while spectroscopic properties were investigated by absorption spectroscopy and spectrally resolved fluorescence imaging. We also tested the possible interaction of the created NPs with living algae for their potential use for environmental research. Employing such ultrashort laser opens route to provide on-demand production of NP's in-situ at even factory environment

Time-resolved fluorescence spectroscopy investigation of the effect of 4-hydroxynonenal on endogenous NAD(P)H in living cardiac myocytes

International audienceLipid peroxidation is a major biochemical consequence of the oxidative deterioration of polyunsaturated lipids in cell membranes and causes damage to membrane integrity and loss of protein function. 4-hydroxy-2-nonenal (HNE), one of the most reactive products of n-6 polyunsaturated fatty acid peroxidation of membrane phospholipids, has been shown to be capable of affecting both nicotinamide adenine dinucleotide (phosphate) reduced [NAD(P)H] as well as NADH production. However, the understanding of its effects in living cardiac cells is still lacking. Our goal was to therefore investigate HNE effects on NAD(P)H noninvasively in living cardiomyocytes. Spectrally resolved lifetime detection of endogenous fluorescence, an innovative noninvasive technique, was employed. Individual fluorescence components were resolved by spectral linear unmixing approach. Gathered results revealed that HNE reduced the amplitude of both resolved NAD(P)H components in a concentration-dependent manner. In addition, HNE increased flavoprotein fluorescence and responsiveness of the NAD(P)H component ratio to glutathione reductase (GR) inhibitor. HNE also increased the percentage of oxidized nucleotides and decreased maximal NADH production. Presented data indicate that HNE provoked an important cell oxidation by acting on NAD(P) H regulating systems in cardiomyocytes. Understanding the precise role of oxidative processes and their products in living cells is crucial for finding new noninvasive tools for biomedical diagnostics of pathophysiological states. (C) 2013 Society of Photo-Optical Instrumentation Engineers (SPIE

Biosensing the presence of nanoparticles using endogenous fluorescence in live algae

&lt;p&gt;Nanoparticles (NPs) from various metals (Zinc, Nickel, Cobalt, Copper) were designed and fabricated by direct synthesis using femtosecond laser ablation in liquids. Employing confocal microscopy with spectral detection and fluorescence lifetime imaging (FLIM), we have evaluated interaction of fabricated NPs with living Chlorella sp. algae by means of their naturally presented endogenous fluorescence. Live cell imaging was done in spectral region 500-550 nm and 650-710 nm to evaluate the effect of NPs on both, the green and the red fluorescence that is derived from flavonoids/carotenoids and chlorophylls respectively. We observed fluorescence intensity decrease in the red spectral region by all but Ni NPs. The presence of NPs also lead to an increase in the blue fluorescence at 477-488 nm, possibly resulting from reflected light. Gathered observations constitute the first step towards creation of methodological approaches for fast natural biosensing of the effects of environmental pollution directly in live algae.&lt;/p&gt

Evaluation of newly synthesized potential NLO-phores for 2-photon and SHG imaging

&lt;p&gt;Our contribution is focused on broadening of the spectrum of available non-linear optical (NLO)-phores (contrast agents for nonlinear optical microscopy) by design and synthesis of new organic dyes with appropriate optical properties. One of the main pre-requisites of microscopy utilizing non-linear excitation is the existence of molecules that are able to provide NLO response for the second-harmonic generation (SHG) or for the two-photon excited fluorescence (TPEF). Many molecules naturally occurring in living tissue such as collagens or NAD(P)H were successfully used in this regard, but there is a natural interest in broadening of the spectrum of available NLO-phores. Gathered results confirm applicability of the newly synthesized dyes as new potential NLO-phores for confocal laser scanning microscopy with nonlinear excitation in rat aorta.&lt;/p&gt

Sensing the interaction of living organisms with microplastics by microscopy methods

&lt;p&gt;Environmental pollution by microplastics (MPs) represents a serious burden of the 21st century. Sensing the interactions of photosynthetic organisms with MPs is based on the study of their endogenous fluorescence derived from chlorophylls. Fluorescently labelled custom-made MPs were tested. We also recorded endogenous fluorescence of the moss in the presence of "naturally-occurring" MPs (polyethylene content of 2 mg/g, non fluorescent) in suspended matter (SM) from the river Rhine. Performed experiments evaluated the distribution of the MPs, as well as the sensitivity of endogenous fluorescence of chlorophylls to their presence. Understanding the interaction of living organisms with MPs will help to assess the impact of this environmental pollution and eventually to propose new approaches for its removal from water sources.&lt;/p&gt