New artificial hematophagy system with attractive polymeric biofilm for maintenance of Culex quinquefasciatus (Diptera: Culicidae) in the laboratory.

BACKGROUND: Maintaining mosquito colonies in the laboratory requires a blood supply so that females' oocytes can mature and oviposition can take place. In this study, a new artificial hematophagy system for colonization and maintenance of Culex quinquefasciatus in the laboratory was developed and tested. METHODS: We developed an attractive polymeric biofilm including 25% L-lactic acid for use as a membrane in an artificial hematophagy system and compared the feeding rate of females with Parafilm-M®. We also evaluated the oviposition rate, larval survival and adult emergence of females fed through the attractive biofilm. RESULTS: The average percentage of female Cx. quinquefasciatus fed through the attractive biofilm was 87%, while only 20% became engorged with Parafilm-M® (p < 0.0001). Feeding through the attractive biofilm developed in this study produced high levels of evaluated biological parameters; the percentage of egg laying by females that underwent artificial hematophagy through the biofilm was 90%, with an average of 158 eggs per raft. From these eggs, 97% of the larvae hatched, of which 95% reached the pupal stage. The adult emergence rate corresponded to 93% of pupae. CONCLUSIONS: Insects fed with attractant through the biofilm system had a higher engorgement rate compared to those fed through Parafilm-M®. Our study is preliminary and suggests that polymeric biofilm has great potential for artificially feeding mosquitoes in the laboratory. Based on this research, new studies will be carried out with biofilm and different systems.

Antimicrobial activity of geranium (Pelargonium graveolens) essential oil and its encapsulation in carioca bean starch ultrafine fibers by electrospinning.

Geranium (Pelargonium graveolens) is known for being an aromatic plant rich in bioactive compounds with antibacterial properties. In this study, geranium essential oil (GEO) was extracted and encapsulated in ultrafine bean starch fibers produced by electrospinning as an antibacterial agent. GEO revealed a composition rich in volatile compounds, including citronellol, cis-geraniol, ß-linalool, citronellyl formate, and linalool formate. In its free form, GEO exhibited high antibacterial activity against pathogenic bacteria strains (L. monocytogenes, S. aureus, and E. coli). The bean starch fibers, produced with and without the addition of GEO, were uniform and continuous, with an average diameter ranging from 249 to 373 nm. Confocal analysis indicated a uniform distribution of GEO in the fibers, with a loading capacity of 54.0 %, 42.9 %, and 36.5 % for 20 %, 30 %, and 40 % GEO concentrations, respectively. Remarkably, fibers containing 40 % GEO showed a significant reduction in tested bacteria (L. monocytogenes, S. aureus, and E. coli), suggesting promising applications in preventing losses and extending the shelf life of food through active packaging.

Curcumin-loaded nanocapsules: Influence of surface characteristics on technological parameters and potential antimalarial activity.

The present study aimed to develop nanocapsules (NCs) loaded with curcumin (CCM) using different coatings, comparing the effect of these coatings on physicochemical properties of NCs. NCs were prepared by interfacial deposition of performed polymer, using different polymers as coatings (P80, PEG, Chitosan and Eudragit RS100®) and then, characterized in detail by different techniques (AFM, FTIR, DSC, XRD, among others). In vitro studies were performed, evaluating the release profile, cytotoxicity and antimalarial activity of CCM-loaded NCs. Overall, all CCM-loaded NCs samples exhibited typical characteristics as nanometric size, coating-dependent zeta potential, acidic pH value, span values below 2, homogeneous morphology and CCM-distribution in pseudophases of type VI (for all of coatings). Experimental results showed that CCM remains stable in lipid-core of NCs, maintaining its physicochemical and biological properties after nanoencapsulation process. In vitro release assays showed that nanoencapsulation was an efficient strategy to controlled release of CCM and P80-coated NCs presented slowest CCM-release considering all nanoformulations tested. Still, CCM-loaded NCs presented no cytotoxic effect. Also, all CCM-loaded NCs showed a perceptible antimalarial activity independently of their coatings (anionic and cationic), with more expressive results for CS-coated NCs. In conclusion, findings for CCM-loaded NCs and their different coatings seem to be a promising strategy to improve your biological activity.