No abstract

Combining traditional medicine with nanotechnology therefore opens the door to innovative strategies for treating skin and soft tissue infections (SSTIs) and also contributes to the fight against the rise of antimicrobial resistance. Acanthospermum australe (Loefl.) Kuntze is a medicinal plant used by indigenous peoples in northeastern Argentina to treat SSTIs. Spherical and stable silver nanoparticles (AgNPs) of 14 ± 2 nm were synthesized from the aqueous extract of A. australe and silver nitrate. The antimicrobial activity against main species causing SSTIs and cytotoxicity on peripheral blood mononuclear cells of AgNP solution and its synthesis components were evaluated. Compared to its synthesis components, AgNP solution showed greater antimicrobial activity and lower cytotoxicity. The antimicrobial activity of AgNPs was due to the silver and not to the metabolites of the aqueous extract present on the surface of the nanoparticles. The plant extract played an important role in the formation of stable AgNPs and acted as a modulator of cytotoxic and immune responses.

Silver nanoparticles (AgNPs) induce diverse cell-death mechanisms, similar to those promoted by anticancer chemotherapeutics; however, they have not been tested in vivo because their action is not limited to cancer cells. Therefore, in vivo evaluations of their effectiveness should be developed with targeting systems. Breast cancer shows changes in the sugar expression patterns on cell surfaces, related to cancer progression and metastases; those changes have been identified previously by the specific binding of soybean agglutinin (SBA). Here is proposed the use of SBA to target the AgNP activity in breast cancer. For that, the present work reports the synthesis of AgNPs (3.89 ± 0.90 nm) through the polyol method, the generation of AgNP nanocarriers, and the bioconjugation protocol of the nanocarrier with SBA. The free AgNPs, the AgNP nanocarriers, and the SBA-bioconjugated AgNP nanocarriers were tested for cytotoxicity in breast cancerous (MDA-MB-231and MCF7) and non cancerous (MCF 10A) cells, using the MTT assay. AgNPs demonstrated cytotoxic activity in vitro, the non cancerous cells (MCF 10A) being more sensible than the cancerous cells (MDA-MB-231 and MCF7) showing LD(50) values of 128, 205, and 319 μM Ag, respectively; the nanoencapsulation decreased the cytotoxic effect of AgNPs in non cancerous cells, maintaining or increasing the effect on the cancer-derived cells, whereas the SBA-bioconjugation allowed AgNP cytotoxic activity with a similar behavior to the nanocarriers. Future experiments need to be developed to evaluate the targeting effect of the SBA-bioconjugated AgNP nanocarriers to study their functionality in vivo.