Over the last decades, multidrug-resistant bacteria have emerged and spread, increasing the number of bacteria, against which commonly used antibiotics are no longer effective. It has become a serious public health problem whose solution requires medical research in order to explore novel effective antimicrobial molecules. On the one hand, antimicrobial peptides (AMPs) are regarded as good alternatives because of their generally broad-spectrum activities, but sometimes they can be easily degraded by the organism or be toxic to animal cells. On the other hand, cationic carbosilane dendrons, whose focal point can be functionalized in many different ways, have also shown good antimicrobial activity. In this work, we synthetized first- and second-generation cationic carbosilane dendrons with a maleimide molecule on their focal point, enabling their functionalization with three different AMPs. After different microbiology studies, we found an additive effect between first-generation dendron and AMP3 whose study reveals three interesting effects: (i) bacteria aggregation due to AMP3, which could facilitate bacteria detection or even contribute to antibacterial activity by preventing host cell attack, (ii) bacteria disaggregation capability of second-generation cationic dendrons, and (iii) a higher AMP3 aggregation ability when dendrons were added previously to peptide treatment. These compounds and their different effects observed over bacteria constitute an interesting system for further mechanism studies.

Deparment of Organic and Inorganic Chemistry University of Barcelona 08028 Barcelona Spain

Faculty of Science J E Purkinje University České mládeže 8 400 96 Ústí nad Labem Czech Republic

Institute for Advanced Chemistry of Catalonia CSIC 08034 Barcelona Spain

Instituto de Investigación Química Andrés M del Río UAH 28801 Alcalá de Henares Spain

Instituto Ramón y Cajal de Investigación Sanitaria IRYCIS 28034 Madrid Spain

Networking Research Center on Bioengineering Biomaterials and Nanomedicine 28029 Madrid Spain

School of Chemistry and Physics University of KwaZulu Natal 4001 Durban South Africa

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