Chitosan, Carbon Quantum Dot, and Silica Nanoparticle Mediated dsRNA Delivery for Gene Silencing in Aedes aegypti: A Comparative Analysis

Abstract

In spite of devastating impact of mosquito borne pathogens on humans, widespread resistance to chemical insecticides and environmental concerns from residual toxicity limit mosquito control strategies. We tested three nanoparticles, chitosan, carbon quantum dot (CQD), and silica complexed with dsRNA, to target two mosquito genes (SNF7 and SRC) for controlling Aedes aegypti larvae. Relative mRNA levels were quantified using qRT-PCR to evaluate knockdown efficiency in nanoparticle-dsRNA treated larvae. The knockdown efficiency of target genes correlated with dsRNA mediated larval mortality. Among the three nanoparticles tested, CQD was the most efficient carrier for dsRNA retention, delivery, and thereby causing gene silencing and mortality in Ae. aegypti.

RNA Interference for Mosquito and Mosquito-Borne Disease Control

“…We contend that RNAi could be adapted and implemented using the framework for existing vector control tools, including larvicides, contact and residual sprays, toxic baits, and LLINs. To translate RNAi to field applicability, RNAi triggers likely will need to be combined with biotic (e.g., a virus, yeast or bacterial expression system) or abiotic (e.g., nanoparticle) systems that mediate both protection and uptake of the RNAi trigger [13,27,46,47,48,49,50,51]. An RNAi approach to mosquito control offers a number of advantages over traditional chemical pesticides, including vastly improved species-specificity with diminished environmental toxicity compared with chemical pesticides.…”

“…Biomacromolecular nanoparticles are advantageous as they will be degraded rather than accumulating in the environment. Of these, chitosan has been most widely reported as an RNAi trigger delivery system for mosquitoes, with efficacy when delivered orally to larvae and or injected in pupae and adults tatgetting an array of tissues [46,47,48,49,128,129,158]. Addition of quantum dots has even led to death following oral delivery of dsRNAs suppressing several essential genes in Ae.…”

“…Addition of quantum dots has even led to death following oral delivery of dsRNAs suppressing several essential genes in Ae. aegypti larvae [46]. Cell Penetrating Peptides (CPPs) offer an alternative to chitosan worthy of exploration in mosquito systems.…”

“…By the same logic, mosquitocidal RNAi triggers could be applied to target essential genes for embryogenesis in Attractive Baited Oviposition Traps (ABOTs) [43,44,45]. In both baited strategies and more traditional insecticidal delivery approaches (ultra-low volume or residual sprays, or LLINs), RNAi triggers may be more efficacious in combination with biotic (e.g., a virus, yeast or bacterial expression system) or abiotic (e.g., nanoparticle) systems that mediate both protection and uptake of RNAi triggers [13,27,46,47,48,49,50,51]. …”

RNA Interference of the Muscle Actin Gene in Bed Bugs: Exploring Injection Versus Topical Application for dsRNA Delivery

“…Injection has been a reliable method of dsRNA delivery into blood-feeding insects, such as bed bugs, ticks, triatomine bugs, but this technique is not practical for the field application (Araujo et al 2006, Kocan et al 2007, Zhu et al 2012). Other dsRNA delivery approaches explored for pest management include topical application, soaking, feeding of transgenic microorganism expressing dsRNA, nanoparticles and plants expressing dsRNA (Baum et al 2007, Pridgeon et al 2008, Ghormade et al 2011, Wang et al 2011, Zhu et al 2011, Das et al 2015, Kim et al 2015, Whitten et al 2016). …”