iBB

A pandemic can turn the world upside down. We recently had this hard experience, which made us reflect (a lot) on the importance of science and how it is the stronghold of our survival as a species (we have persisted for at least 200 thousand years!). Resistance to antibiotics and antifungals is nothing new and seems to have become commonplace (or despised). It is too serious a problem to be reassured, for several reasons. The evolution of multidrug resistance in bacteria and fungi (proven by genetic sequencing), associated with the disinvestment in new drugs by large pharmaceutical multinationals, converges in a (next) pandemic scenario of hypervirulent bacteria and fungi. Antimicrobial resistance is fundamentally based on the ability that bacteria and fungi have acquired to escape the action of available drugs, using mainly three strategies: enzymatic degradation of drugs, alteration of drug target proteins, and alteration of membrane permeability (expression of efflux pumps). Bearing in mind these strategies, a team of researchers from iBB-IST (led by Prof. Vasco Bonifácio) in collaboration with researchers from CQE-IST and ITQB-NOVA, designed, and produced antimicrobial polyurea pharmadendrimers, a new class of antibiotics and antifungals. These pharmadendrimers have excellent activity (in vitro and in vivo) against multidrug-resistant bacteria and fungi from clinical isolates collected in Portuguese hospitals and clinics. Their administration is safe as they have a very wide therapeutic window, in which they are not cytotoxic and do not cause hemolysis (the main problems of other analogues under investigation, such as antimicrobial peptides). On the other hand, its mechanism of action prevents the development of resistance, an almost impossible mission for bacteria and fungi because it requires a restructuring of their membrane. Antimicrobial pharmadendrimers have been patented, and an international patent application is pending. In an interview to the RTP TV channel, on the program “O Desafio do Superior em Portugal”, Dr. Rita Pires, a researcher on the team, talks about this invention (video). The research work was recently published in a high impact international journal.

Photodiodes are on the rise. In the past decade many efforts have been made to deliver cheaper, more flexible, and increasingly better performing photodiode devices. The demand for enhanced optoelectronics led to the development of new inorganic, organic, and hybrid materials. A tutorial review published in Journal of Materials NanoScience by Rita Pires and Vasco Bonifácio from BSIRG-iBB describes in detail the working principles, the characterization, fabrication (types and architectures) and major applications of photodiodes. Recent applications, mainly in imaging, sensing and healthcare are also presented.

Polyurea oxide (PURO) biodendrimers are a class of dendrimers that can trigger osteogenic differentiation of human mesenchymal stem cells (hMSCs). The effect of PURO biodendrimers in the differentiation of hMSCs was found by the single addition to a standard growth medium for MSCs differentiation (without differentiation inducers, e.g. dexamethasone, ascorbic acid, and β-glycerophosphate). These results, published in ACS Applied Bio Materials by Rita Pires and Vasco Bonifácio from BSIRG-iBB and with colleague João Conde from NOVA Medical School, constitute the first report of in vitro osteodifferentiation fully regulated by synthetic soft polymers. The outstanding role of dendrimers in nanomedicine, under clinic translation, combined with this feature is envisaged to foster PURO dendrimers as an important strategy in cell therapy and regenerative medicine.

Rita Pires won the Photography Award "A flash on chemistry", promoted by the Group of Young Chemists of the Portuguese Society of Chemistry. This Award was aimed at praising the importance of the Periodic Table and of the Chemical Elements through original photographs.

"It's not a vision of Space or any distant planet, what we see is a round-bottom flask. Pure chemistry. Inside, hydrogen builds bridges between the tentacular arms of a polyurea dendrimer. The result is fascinating, a blue, intense and intrinsic fluorescence. The rare phenomenon, also observed in nature during the aggregation of beta sheets of amyloid fibers, is explained by the delocalization of electrons through the hydrogen bonds. It is not a planet, but we travel with our gaze. Chemical elements highlighted: Hydrogen, Nitrogen, Oxygen and Carbon."