RESUMO
Dengue, Zika, chikungunya, and yellow fever are arboviruses transmitted by Aedes aegypti mosquito. In this regard, a number of techniques have emerged aiming to combat its proliferation. Elimination of Aedes aegypti larvae by photodynamic action has been reported as an efficient approach. In this regard, this study was aimed at synthetize and characterize formulations with different proportions (w/w) of the plant-based photolarvicidal curcumin and d-mannitol (CCD 1-4) and their evaluation on sublethal photolarvicidal efficiency, photodegradation profile,solubility, internalization, elimination time, persistence in simulated field, growth of microorganisms in water and the toxicity using an animal models (Zebrafish). CCD 3 (curcumin:d-mannitol 50:50 w/w) showed the best efficacy (LC50-24h = 0.01 mg/L), and also presented the shortest internalization and longest elimination time, 60 min and 8 days, respectively. This formulation caused an extrusion into the intestine and peritrophic membrane. Moreover, CCD 3 showed a photodegradation of 50% (in 24 h) under white fluorescent lamps. In a small-scale field trial, CCD 3 had a residual time of 14 days and abnormal microbial growth was not observed. Finally, CCD 3 did not present any toxicity in Zebrafish, after exposition for 24 h at 100 mg/L. Overall, these results raise the possibility of reducing virus transmission through the controlled photoinactivation of Aedes aegypti larvae using a non-toxic plant-based formulated photolarvicide.
Assuntos
Aedes , Curcumina , Fotoquimioterapia , Infecção por Zika virus , Zika virus , Animais , Curcumina/farmacologia , Larva , Manitol , Mosquitos Vetores , Fotoquimioterapia/métodos , Peixe-ZebraRESUMO
The use of ultraviolet (UV) and blue irradiation to sterilize surfaces is well established, but commercial applications would be enhanced if the light source is replaced with ambient light. In this paper, it is shown that nanofibers can be explored as an alternative methodology to UV and blue irradiation for bacterial inactivation. It is demonstrated that this is indeed possible using spun nanofibers of poly[lactic-co-(glycolic acid)] (PLGA). This work shows that PLGA spun scaffolds can promote photoinactivation of Staphylococcus aureus and Escherichia coli bacteria with ambient light or with laser irradiation at 630 nm. With the optimized scaffold composition of PLGA85:15 nanofibers, the minimum intensity required to kill the bacteria is much lower than in antimicrobial blue light applications. The enhanced effect introduced by PLGA scaffolds is due to their nanofiber structures since PLGA spun nanofibers were able to inactivate both S. aureus and E. coli bacteria, but cast films had no effect. These findings pave the way for an entirely different method to sterilize surfaces, which is less costly and environmentally friendly than current procedures. In addition, the scaffolds could also be used in cancer treatment with fewer side effects since photosensitizers are not required.