LPS also induces HO-1 protein expression in leukocytes migrating to the air pouch exudates, causing them to exhibit higher levels of CO than would be expected in the absence of LPS. Ex vivo studies on mice with a subcutaneous air pouch use Lipopolysaccharides (LPS) to induce an inflammatory reaction characterized by plasmatic exudation and migration of leukocytes to the cavity. 3 In vitro studies use confocal and multi-photon microscopy to visualise the release of CO by carbon monoxide releasing molecules CORM-3 and hemin in live cells. Our novel molecular probes provide one- or two-photon fluorogenic detection of CO in biological environments using the IDA paradigm pioneered by Anslyn. 2 One of the major obstacles limiting progress in understanding the biological role of CO and its therapeutic application is the lack of real-time methods to selectively track CO in biological systems. 1 The potential of CO as a therapeutic agent has received significant attention, particularly since CO-releasing molecules (CORMs) are capable of liberating controlled amounts of CO in biological systems. In the body, endogenous CO acts as a gaseous signalling molecule serving many functions, including anti-inflammatory, antiapoptotic and anticoagulative roles. This research has received funding from the European Community's Marie Curie Seventh Framework Programme (FP7/2007-2013: n° 316906 (ITN Luminet) and n° 611488 (IRSES Metallacrowns)), La Ligue Contre le Cancer, La Region Centre and ANR Lumiphage. Their unique potential makes them attractive candidates for advanced applications in optical imaging and therefore represents significant breakthroughs toward the creation of a new generation of the NIR optical imaging probes for in vitro and in vivo applications with possibilities for replacement of current probes.ġ.
Presented monometallic and polymetallic Ln 3+-based molecules, macromolecules and nanomaterials possess a superior and complementary optical properties over the currently available commercial fluorescent probes. In particular, i) non-permeable and photostable polymetallic metallacrown (MC) complexes, Yb 3+, demonstrated their applicability for labelling of cell necrosis 2 ii) monometallic L1Nd 3+, the first LnP with excitation and emission wavelengths within the ideal diagnostic window, demonstrated a deeper penetration through tissues of different origin and a more sensitive detection iii) polymetallic nanoparticles represent a major breakthrough in the design of LnPs with improved properties by simplifying screening of efficient chromophores and iv) polymetallic G3P dendrimers, (Ln 8-)G3P-(aza-BODIPY) n, demonstrated possibility for tuning of photophysical properties, photostability and cellular uptake, by controlling the number of chromophores at their periphery and by presence and nature of Ln 3+.
Novel LnPs have been designed and successfully used for visible/NIR in vitro imaging and their advantages over the current fluorescent probes have been demonstrated. Uptake of LnPs by HeLa cells was analyzed by confocal and epifluorescence microscopies and by flow cytometry in the visible/NIR. Absorption/excitation/emission spectra, luminescence lifetimes, quantum yields and photostabilities were measured. (Ln 8-)G3P-(aza-BODIPY) n (n=16,32) were synthesized by coupling of aza-BODIPY with generation-3 polyamidoamine (G3P) dendrimer and interaction with Yb 3+ or Nd 3+ nitrates.
The L1Nd 3+ complex was obtained by interaction between the ligand L1 and Nd 3+ nitrate (n=4,8) nanoparticles by encapsulation of 1,4- or 1,8- dihydroxyanthraquinones and Yb 3+ triflates in polystyrene beads and their functionalization with polyethylene glycol. Yb 3+ was synthesized by reaction of pyrazinehydroxamic acid with Zn 2+ and Yb 3+ triflates. 1 Herein, we present several families of LnPs.
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Low absorbance of free Ln 3+ requires the use of appropriate chromophores for sensitization of their luminescence. sharp emission bands not affected by the microenvironment and high resistance toward photobleaching. New generation of optical imaging agents, lanthanide(III) (Ln 3+)-based probes (LnPs), possess unique optical properties e.g. In particular, imaging in the near-infrared (NIR) region attracts significant attention due to reduced autofluorescence and light scattering. Fluorescence optical imaging is a highly sensitive technique.