iBB

Gold(III) bisdithiolate complexes have been shown as potential antimicrobial and antitumoral agents. In particular, the complex [Au(cdc)2]− (cdc=cyanodithioimido carbonate) displayed antimicrobial and outstanding antitumor activity against the ovarian cancer cells A2780 and A2780cisR, which are sensitive and resistant to cisplatin, respectively. Yet, poor water solubility may hinder its clinical use. Block copolymer micelles (BCMs) have demonstrated great potential as nanocarriers capable of delivering hydrophobic drugs, increasing their solubility and stability, and improving their bioavailability and circulation time in blood, with reduced side effects. In this work, published in the journal Pharmaceutics, the potential of BCM-[Au(cdc)2] as a novel drug-delivery system was addressed. The BCM-[Au(cdc)2] micelles were prepared with a loading efficiency of 64.6% and a loading content of 35.3 mg [Au(cdc)2]−/gBCM, they were also homogenous and good candidates for drug delivery. Cytotoxic activity studies against A2780/A2780cisR cells showed that BCM-[Au(cdc)2] maintained relevant cytotoxic activity comparable to the cytotoxicity observed for the same concentration of gold complexes. The Au uptake in A2780 cells, determined by PIXE, was ca. 17% higher for BCMs-[Au(cdc)2] compared to [Au(cdc)2]−. The BCMs-[Au(cdc)2] presented also antimicrobial activity against S. aureus Newman and C. glabrata CBS138. In summary this paper shows the results of the potential of BCM-[Au(cdc)2] for drug delivery and its promising anticancer and antimicrobial activities.

This study was led by Dr. Célia Fernandes and Dr. Fernanda Marques, both from Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico. The iBB members Teresa Pinheiro, Jorge Leitão and Sílvia Sousa collaborated in this work performing the cellular uptake analysis and the antimicrobial activities of BCMs.

In a recent paper IBB researchers led by Teresa Pinheiro and working in collaboration with IPMA and C2TN/IST, studied how diatoms were keen to metal uptake. By using nuclear microscopy techniques it was possible to map intracellular elemental distributions. Diatoms clearly respond to excess metal levels, by changing cytoplasm morphology, concentrating added metals, and altering Fe transport mechanisms. This work was selected as a “Hot article” in Metallomics journal.  Click on title to learn more.

Photo details: Nuclear microscopy image of calcium (blue, low concentration; red, high concentration) in diatom Coscinodiscus eccentricus, showing chloroplast distribution changes in cells exposed to metal overload.