microporous
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Microporous organic polymers (MOP) of a new type have been synthesised in high yields by a simple coordination polymerization of 1,3-diethynylbenzene, 1,4-diethynylbenzene and 4,4'-diethynylbiphenyl catalysed by [Rh(cod)acac] and [Rh(nbd)acac] complexes. The new MOPs are non-swellable polyacetylene-type conjugated networks consisting of ethynylaryl-substituted polyene main chains that are crosslinked by arylene linkers. Prepared MOP samples have a mole fraction of branching units (by (13)C CP/MAS NMR) from 0.30 to 0.47 and exhibit the BET (Brunaer-Emmett-Teller) surface up to 809 m(2) g(-1) and hydrogen uptake up to 0.69 wt% (77 K, H2 pressure 750 torr).
- Klíčová slova
- Biokop I,
- MeSH
- lidé MeSH
- následné studie MeSH
- pooperační komplikace MeSH
- poréznost MeSH
- protézy a implantáty klasifikace škodlivé účinky využití MeSH
- transplantace rohovky MeSH
- Check Tag
- lidé MeSH
This study reports the first Co2 (CO)8 -catalyzed [2+2+2] polycyclotrimerization by the transformation of internal ethynyl groups of aromatic diyne monomers. The reaction yields polycyclotrimers of polyphenylene-type with either hyperbranched or partly crosslinked architecture. The homopolycyclotrimerization of the monomers with two ethynyl groups per one molecule, namely 1,4-bis(phenylethynyl)benzene, 4,4'-bis(phenylethynyl)biphenyl, and 4-(phenylethynyl)phenylacetylene, gives partly crosslinked, insoluble polyphenylenes. The soluble, hyperbranched polyphenylenes are generated via copolycyclotrimerization of 1,4-bis(phenylethynyl)benzene with 1,2-diphenylacetylene (average number of ethynyl groups per monomer molecule < 2). This one-step polycyclotrimerization path to hyperbranched or partly crosslinked polyphenylenes is an alternative to the synthesis of these polymers by Diels-Alder transformation of substituted cyclopentadienones. All polyphenylenes prepared exhibit photoluminescence with emission maxima ranging from 381 to 495 nm. Polyphenylenes with a less compact packing of segments are microporous (specific surface area up to 159 m2 g-1 ), which is particularly important in the case of soluble polyphenylenes because they can be potentially used to prepare microporous layers.
Závěrečná zpráva o řešení grantu Agentury pro zdravotnický výzkum MZ ČR
Nestr.
Transplantace (Tx) Langerhansových ostrůvků (LO) v klinické praxi je limitovaná mimo jiné vysokým procentem buněk ztracených během 2 dnů po Tx, a nutností trvalé imunosupresívní léčby. Proto se hledá alternativní způsob Tx, který by významně zvýšil úspěšnost přihojení, umožnil lokální ochranu před rejekcí a bezpečné vyjmutí štěpu v případě komplikací. Podle literárních i našich předběžných výsledků je klíčové dostatečné zásobení kyslíkem. Takové podmínky může zajistit dutina uměle vytvořená v podkoží příjemce pomocí polymerního skeletu s navázanými funkčními molekulami (VEGF, CXCL-12), které umožní řízené prorůstání vaziva s kapilárami a lokálně omezí aktivitu imunokompetentních buněk. Plánujeme posoudit efekt mikroporezní struktury skeletu, VEGF navázaného na skelet a řízeného uvolňování molekuly CXCL-12 ze skeletu nebo mikročástic, které budou součástí suspense při Tx LO, na vaskularizaci dutiny a dlouhodobou funkčnost transplantovaných LO u potkanů. Technika je slibná jak pro allogenní Tx LO pro diabetiky 1. typu, tak zejména pro autoTx LO po totální pankreatektomii.; The clinical transplantation (Tx) of pancreatic islets (PI) is limited by a significant cell loss during 2 days after Tx, and by permanent immunosuppressive therapy. Therefore, there is a need of an alternative Tx technique, which would significantly improve the engraftment, the local immune protection as well as the safe graftectomy. Based on the literature as well as our preliminary data the sufficient oxygen supply is a crucial factor. The cavity created under skin by implantation of a polymer microporous scaffold can provide adequate conditions. VEGF attached to the scaffold can control the ingrowth of connective tissue with capillaries and cytokine CXCL-12 can restrict activity of immunocompetent cells. We will evaluate the effect of VEGF bound to polymer scaffolds on the cavity vascularization and controlled release of CXCL-12 from scaffolds or microparticles on PI survival. The optimized cavity can improve outcomes of allogeneic PI Tx for Type-1 diabetic patients as well as of autologous PI Tx in patients after total pancreatectomy.
- MeSH
- krevní oběh MeSH
- krysa rodu rattus MeSH
- lidé MeSH
- modely nemocí na zvířatech MeSH
- remodelace cév MeSH
- subkutánní tkáň MeSH
- tkáňové podpůrné struktury MeSH
- transplantace Langerhansových ostrůvků MeSH
- vstřebatelné implantáty MeSH
- vyvíjení léků MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- lidé MeSH
- zvířata MeSH
- Publikační typ
- hodnotící studie MeSH
- Konspekt
- Patologie. Klinická medicína
- NLK Obory
- transplantologie
- angiologie
- NLK Publikační typ
- závěrečné zprávy o řešení grantu AZV MZ ČR
BACKGROUND: In vitro labelling of cells and small cell structures is a necessary step before in vivo monitoring of grafts. We modified and optimised a procedure for pancreatic islet labelling using bimodal positively charged poly(lactic-co-glycolic acid) nanoparticles with encapsulated perfluoro crown ethers and indocyanine green dye via microporation and compared the method with passive endocytosis. RESULTS: Pancreatic islets were microporated using two pulses at various voltages. We tested a standard procedure (poration in the presence of nanoparticles) and a modified protocol (pre-microporation in a buffer only, and subsequent islet incubation with nanoparticles on ice for 10 min). We compared islet labelling by microporation with labelling by endocytosis, i.e. pancreatic islets were incubated for 24 h in a medium with suspended nanoparticles. In order to verify the efficiency of the labelling procedures, we used (19)F magnetic resonance imaging, optical fluorescence imaging and confocal microscopy. The experiment confirmed that microporation, albeit fast and effective, is invasive and may cause substantial harm to islets. To achieve sufficient poration and to minimise the reduction of viability, the electric field should be set at 20 kV/m (two pulses, 20 ms each). Poration in the presence of nanoparticles was found to be unsuitable for the nanoparticles used. The water suspension of nanoparticles (which served as a surfactant) was slightly foamy and microbubbles in the suspension were responsible for sparks causing the destruction of islets during poration. However, pre-microporation (poration of islets in a buffer only) followed by 10-min incubation with nanoparticles was safer. CONCLUSIONS: For labelling of pancreatic islets using poly(lactic-co-glycolic acid) nanoparticles, the modified microporation procedure with low voltage was found to be safer than the standard microporation procedure. The modified procedure was fast, however, efficiency was lower compared to endocytosis.
- Publikační typ
- časopisecké články MeSH
