Translocation of 40 nm diameter nanowires through the intestinal epithelium of Daphnia magna

Abstract

Nanowires (NWs) have unique electrical and optical properties of value for many applications including lighting, sensing, and energy harnessing. Consumer products containing NWs increase the risk of NWs being released in the environment, especially into aquatic ecosystems through sewage systems. Daphnia magna is a common, cosmopolitan freshwater organism sensitive to toxicity tests and represents a likely entry point for nanoparticles into food webs of aquatic ecosystems. Here we have evaluated the effect of NW diameter on the gut penetrance of NWs in Daphnia magna. The animals were exposed to NWs of two diameters (40 and 80 nm) and similar length (3.6 and 3.8 μm, respectively) suspended in water. In order to locate the NWs in Daphnia, the NWs were designed to comprise one inherently fluorescent segment of gallium indium phosphide (GaInP) flanked by a gallium phosphide (GaP) segment. Daphnia mortality was assessed directly after 24 h of exposure and 7 days after exposure. Translocation of NWs across the intestinal epithelium was investigated using confocal fluorescence microscopy directly after 24 h of exposure and was observed in 89% of Daphnia exposed to 40 nm NWs and in 11% of Daphnia exposed to 80 nm NWs. A high degree of fragmentation was observed for NWs of both diameters after ingestion by the Daphnia, although 40 nm NWs were fragmented to a greater extent, which could possibly facilitate translocation across the intestinal epithelium. Our results show that the feeding behavior of animals may enhance the ability of NWs to penetrate biological barriers and that penetrance is governed by the NW diameter.

Cellular traction forces: a useful parameter in cancer research

“…GaInP nanowire segments have been shown to exhibit bright near infra-red photoluminescence with negligible bleaching and are therefore well-suited when stable emission is required during longitudinal measurements. [21][22][23] The fact that only the tip of the nanowire emits light allows for small variations in focus to occur without any loss of precision in the force estimation based on the localization of the nanowire tip.…”

The Nano–Intestine Interaction: Understanding the Location‐Oriented Effects of Engineered Nanomaterials in the Intestine

“…[55] A recent study illustrated that a high degree of fragments was observed for GaP/GaInP nano wires after ingestion by the Daphnia, which facilitated the trans location of NMs across the intestinal epithelium. [56] Another case is that the addition of intestinal simulated fluid changed the size and aggregation state of polyvinylpyrrolidone (PVP) coated Ag NMs and increased the cellular uptake and toxicity of NMs on Caco2 cells. [52] The reason for this phenomenon might be that the release of silver ion mediated by intestinal fluid is involved in the generation of hydroxyl radical.…”

Disaggregation of gold nanoparticles by Daphnia magna

“…It is also of importance to understand the aggregation properties of nanoparticles in an aqueous environment, as well as how they are affected by the digestive system of the organisms. Nanomaterials have been detected inside Daphnia after incubation (Scanlan et al 2013;Mattsson et al 2016) possibly by being passively transported through the feeding current of the animal. Changes in particle aggregation state in the surrounding medium are likely to affect the filtration and uptake of nanoparticles by Daphnia.…”