Session: Undergraduate Research Posters: Nanochemistry:

Daphnia Magna is a microcrustacean that provides a versatile and economical model to perform bioassays on the effects of muscle relaxants, based on the time of exposure, the change in the heartbeat, and its lethal dose. The objective of the research was to determine the effects of short-term and long-term exposure to muscle relaxants Orphenadrine (Norflex) and Nabumetone (Relafen) using silver and gold nanoparticles in Daphnia Magna. The heart and mortality rates were monitored under different conditions: drugs, silver and gold nanoparticles, and a combination of these factors. The nanoparticles were characterized using Dynamic Light Scattering (DLS) and UV Spectrophotometry. The size of silver and gold nanoparticles were 33 nm and 24 nm respectively. The lethal concentration of 50% of the population (LC ) was 3.5 mg for Orphenadrine concentrations, however when combined with gold nanoparticles the time of death took place 30 minutes later. Nevertheless, the same concentrations of the drugs combined with gold and silver nanoparticles decreased its toxicity. These studies were further extended to compare the effects of these drugs on a second generation of Daphnia magna. Second generation of Daphnia Magna showed a greater tolerance to the treatments than the first generation. Additionally, we continued the investigation by obtaining the Daphnia Magna heartbeats through a microscope with video recording adapter. The gold and silver nanoparticles counteract the effect of the drugs on the daphnia magna, stabilizing the heart beats in comparison with the drugs alone. The drugs cause a continuous decreasing of 3% of the heart beats every ten minutes. Our results showed that nanoparticles prolonged the survival and hearts rate of the organism.

Janay Velez Leon

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