Aedes aegypti is one of the mosquito species with major epidemiological importance in Brazil, involved with the transmission of the arboviruses such as Dengue, Chikungunya and Zika. Since the mosquito is well adapted to the urban environments, where there are large amounts of breeding sites for larvae and pupae, its control has become increasingly difficult. Since 1996, the usual control is made by using chemical larvicides, but the continued use of some of these compounds has led to the selection of A. aegypti resistant populations. Therefore, the search for new insecticidal substances is necessary to guarantee the control of this specie. Our goal is to establish a new larvicide with high toxicity without the drawback of resistance. For this, we developed a low-cost green synthesized silver nanoparticles with a poly(methacrylic acid) outer layer, catalyzed with ultra violet light. We tested nanoparticles samples produced from different batches in laboratory bioassays against fourth-instar larvae. The results showed a desired toxic activity, presenting 10% to 100% of mortalities in concentrations ranging from 0.01 to 1.1 ppm, and from the bioassay we have obtained LC50 = 0.027 ppm and LC90 = 0.044 ppm, after 24 hours of exposure. Imaging the threated larvae by optical microscopy and optical coherence tomography helped to clarify the potential larvae death mechanism. These results associated with the simplicity and low cost of production of these silver nanoparticles, reveal their great potential for the development of products to control of A. aegypti larvae.
Mariana T. Carvalho, Gisele S. de Santana, Audrey N. de Andrade, Amanda Cabral, Nairane da Silva Rosa-Leão, Maria Alice V. de Melo-Santos, and Anderson S. L. Gomes, "Exploiting silver nanoparticles with PMAA against aedes aegypti larvae development: potential larvicidal activity," Proc. SPIE 10507, Colloidal Nanoparticles for Biomedical Applications XIII, 105070O (Presented at SPIE BiOS: January 28, 2018; Published: 23 February 2018); https://doi.org/10.1117/12.2291573.
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Study of self-shadowing effect as a simple means to realize nanostructured thin films and layers with special attentions to birefringent obliquely deposited thin films and photo-luminescent porous silicon