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- Green polymers toward nanobiotechnology(I): synthesis of glycopolypeptides and their analoguesPublication . Wang, Zhao; Neves, Ana Rute; Olim, Filipe; Tomás, Helena; Tang, Shi; Sheng, RuilongHarnessing natural-based renewable molecular resources to construct functional synthetic green polymers is a promising research frontier at the interface of sustainable/green chemistry, polymer chemistry and nanobiotechnology. As natural glycoprotein mimics/analogues and biocompatible building blocks of nanobio- materials, synthetic functional glycopolypeptides and their structural/functional analogues have attracted great attentions in recent years. This mini-perspective article reviewed current synthetic strategies and methods of glycopolypeptides and their analogues. The pros and cons of the synthesis protocols were discussed, moreover, possible future perspectives in this field were also stated.
- Preliminary studies on the use of exosomes as dendrimer carriersPublication . Olim, José Filipe Sousa de; Tomás, Helena Maria Pires Gaspar; Rodrigues, João Manuel CunhaEukaryotic and prokaryotic cells can release vesicles into the biological fluids that differ in size and mechanism of biogenesis. In recent years, particular attention has been paid to exosomes which are naturally occurring nanoparticles (50 – 150 nm) that have been found in various biological fluids and are recognized as having an important role in intercellular communication and other biological processes. Human mesenchymal stem cells (hMSCs) are multipotent cells that can be found in different tissues in the adult. hMSCs have a large capacity for ex vivo expansion and show immunosuppressive properties, making them the ideal source of exosomes for biomedical applications. Dendrimers are nanoscale molecules that have promising properties as drug/gene delivery vehicles and, as such, their inclusion inside hMSCs exosomes may be a way for their easier spreading and target reaching in the body. The present work was focused on the hypothesis that exosomes can be loaded before their isolation from cells by simple cell exposure to dendrimers. First, dendrimers were labelled with rhodamine and then characterized by 1H NMR, FTIR, UV/Vis spectroscopy, and fluorescence spectroscopy. Then, the effect of the pH in the stability of the fluorescence emission of these conjugates was study, as well as their cytotoxicity behavior and kinetics of cellular internalization. After, a protocol for exosome isolation was established using a precipitation-based approach and the isolated exosomes were characterized by DLS, TEM and acetylcholinesterase activity. hMSCs were then exposed to a solution containing the labelled dendrimers and the released exosomes were collected to evaluate the presence of the dendrimers inside. Contrary to what was expected, the dendrimers were not excreted inside exosomes and, instead, were accumulated in the cellular perinuclear zone. By fluorescence microscopy and using specific biochemical markers, it was possible to co-localize the conjugated dendrimers with the Golgi complex and the endoplasmic reticulum.