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Gold nanorods (GNRs) are increasingly being studied for diagnostic and therapeutic purposes. Green synthesis based methods with natural compounds as additives stand out as a hope in terms of better synthesis methodology, with advantages of producing potentially less toxic and, perhaps, biologically active GNRs due to influence of natural additives used during synthesis. Exploring green chemistry using different natural phenolic compounds, the present work reveals different in vitro activity of GNRs evaluated against different parasites that causes skin infectious diseases compared to GNRs produced by convencional seed mediated method. This approach brings advantages in producing active GNRs, with ease calling, less cytotoxic and with a better selectivity index (SI) than GNRs synthesized by conventional seed mediated synthesis, opening new possibilities for therapies. Natural compounds used in green syntheses were gallic acid (GA), resveratrol (RSV) and a purified fraction of the hydroalcoholic extract of Stryphnodendron obovatum. GNRs exhibited great activity against Leishmania braziliensis, and the dermatophytes Tricophyton rubrum, T. interdigitale and Microsporum gypseum. The anti-Leishmania and antidermatophytic activity of GNRs reinforce the applicability of GNRs in biomedical field and the influence of synthesis method in biological activity, showing benefits related to the seedless synthesis with natural compounds. In addition, these preliminary results indicate the possibility of exploring at maximum the physical and chemical properties of GNRs in addition to the biological activity itself, such as the development of topical antiparasitic formulations for association with phototherapy., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Schistosomiasis is an important parasitic disease affecting >207 million people in 76 countries around the world and causing approximately 250,000 deaths per year. At present, the main strategy adopted for the control of schistosomiasis is the use of safe chemotherapy, such as praziquantel. However, the high rates of reinfection after treatment restrict the use of this treatment approach and assume the need for other forms of control such as vaccination. Sm29 is a protein that is localized in the Schistosoma mansoni tegument of adult worms and schistosomula and is considered a powerful vaccine candidate. Because of the chemical, physical and immunological characteristics of nanoparticles, nanocarriers have received increasing attention. In the field of nanotechnology, gold nanorods are considered potential vaccine carriers. In this study, we bound S. mansoni rSm29 protein to gold nanorods either directly or by cysteamine functionalization. When the worm burden was evaluated, the AuNRs-NH 2 -rSm29 group of immunized mice showed the best protection level (34%). Following AuNRs-NH 2 -rSm29 immunization, we observed a Th1 immunological response in mice with higher production of IFN-γ, mainly by CD4 + and CD8 + T cells. Furthermore, AuNRs-NH 2 -rSm29 could activate dendritic cells in vitro, enhancing MHCII and MHCI expression and the production of IL-1β in a NLRP3-, ASC- and Caspase-1-dependent manner. In summary, our findings support the use of nanorods as an immunization strategy in vaccine development against infectious diseases., (Copyright © 2018 Elsevier B.V. All rights reserved.)

We report a simple and easy formation of hybrids between multi-wall carbon nanotubes and gold nanorods by one-pot in situ photochemical synthesis. Measurements of surface-enhanced Raman scattering (SERS) through the effect "coffee ring" in visible and near infrared (NIR) show high sensitivity with detection of nanomolar concentrations of aromatic dyes. The formation of nanocomposites between carbon nanotubes and gold nanorods without chemical binders simplifies the preparation. Photochemical synthesis is an advance over the techniques previously published., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Amorphous silica nanowires have been produced by thermal annealing of Si/SiO2/Ni substrate structures at 900 degrees C under an atmosphere of hexamethyldisilazane (HMDS) and hydrogen (H2). The wires have diameter ranging from 35 to 55 nm, which are controlled by the Ni particle size. It is demonstrated that the growth occurs through vapor-liquid-solid mechanisms, and it is proposed that the vapor source is volatile SiO generated from the etching of the Si substrate through active oxidation reactions. The role of the HMDS-H2 atmosphere in promoting such reactions is discussed.