Assessment of SnO 2 nanoparticles’ impact on local Pichoclorum atomus growth performance, cell morphology and metabolites content Touria BOUNNIT, Imen SAADAOUI, Rihab RASHEED, Hareb Al Jabri, Sami SAYADI, Ahmad I. AYESH Faculty, Energy ,Environment &Resource sustainability • Study the impact of nanoparticles (SnO 2 ) on the growth and metabolites cotent of local marine algae isolate Picochlorum atomus (P.atomus) [4]. • The results obtained herein provide information about the environmental risks and/or safe use of nanoparticles. Objective Introduction Results Results In the last two decades, materials science witnessed great developments due to the progress in the synthesis and design of nano- sized materials. The utilization of these materials is notably increased in different applications such as medical, environmental, food production, energy generation,… etc [1, 2]. Tin oxide (SnO 2 ) nanoparticles exhibit novel semiconducting properties that lead to their utilization in optical, electronic, and catalytic applications [2, 3]. However, their wide range of emerging applications increase the probability of their release to the environment which leads to the interaction with the surrounding biological species such as algae. Hence, their novel feature may unfortunately also lead to high activity in biological systems, producing toxicity. The current study investigated the toxicity of SnO 2 nanoparticles on a local marine algae isolate. Herein, we present a toxicity study that focuses on the alterations of nanoparticles for cell membranes, and their indirect effects such as aggregation. Algal growth and metabolites are also monitored in order to explore the nanoparticles impacts. Methodology 1- Assessment of SnO 2 concentrations on P.atomus growth performance : Figure 2: SEM of P.atomus under different SnO2 concentrations: (a): Only P.atomus, (b-f): P.atomus+ different SnO2 concentrations of 100mg/L, 50mg/L, 25mg/L, 5mg/L and 1mg/L respectively after 72h of culture. • The effect of SnO 2 on the algal cells morphology was specific to the SnO 2 dose, • Lower SnO 2 concentrations led to dramatic changes on the cell morphology, • Similar effect on the cell morphology was observed at 1 and 5mg/L, • The effect of SnO 2 decrease with increased concentrations. • Slight effect was observed on the algal cells with 25mg/L of SnO 2 with appearance of SnO 2 agglomeration. • No effect on the cell morphology at high concentration od SnO 2 50-100mg/L with more accentuated agglomeration of the nanoparticles. 2- Morphological effects of SnO2 on P.atomus cells • The SnO 2 presented negative impact on the algae growth that is decreasing with the dose, • The effect of SnO 2 concentrations was dose dependent and the highest impact was observed at 1mg/L. • Similar effect on the algal growth was recorded for 50 and 100 mg/L, highlighting the fact that the saturation can be observed after 50mg/L of SnO 2 . Figure1: Effect of SnO2 concentrations on P.atomus growth qControl: Only Algae and Only Nanoparticles. 3- Effect of different SnO2 concentrations on the metabolites expression SnO2 concentrations (mg/L) Lipids (%) Carbohydrates (%) Proteins (%) Control (0) 28.1 14.16 27.4 5 33.3 19.06 20.7 25 30.7 20.28 20 50 19.1 14.7 27 Due to the similarity in growth under 1-5mg/L and 50-100mg/L SnO2, we selected the following concentrations of 5, 25 and 50mg/L for assessment of metabolite profiling and chlorophyll content. Table 1: effect of different concentrations of SnO2 on the metabolites content • The highest lipid content was observed at the lower SnO 2 concentrations, this can be explained by the stress induced by the nanoparticles to the algal cells. These findings are in correlation with the cell morphology data. • 50mg/L showed the lowest effect on the metabolites content comparing to the control explaining the no effect on the cell morphology, • 25mg/L led to the highest carbohydrates content among the other concentrations investigated. Conclusion • The SnO 2 presented a toxicity on the algae growth that was decreasing with the dose, with lower doses presenting more negative impacts than higher doses, • The slow growth observed at 1-5 mg/L is explained by the dramatic damages caused by the SnO 2 on the cell morphology, • The low negative impact of higher concentrations of SnO 2 (50-100mg/L) is explained by the high agglomeration of ten particles leading to reduced effect on the cell morphology and health, • In accordance with the morphological data, the SnO 2 nanoparticles induced stress which was manifested by an increase in the lipids as molecules helping in attenuating the stress encountered by the cells, and a decrease in the proteins which are involved in the algal growth. References [1] A.I. Ayesh, B. Salah, R. Nawwas, A. Alyafei, S. AlMansouri, L. Al-Sulaiti, Production of flexible nanocomposite membranes for x-ray detectors, Applied Surface Science, 528 (2020) 146958. [2] A.I. Ayesh, A.A. Alyafei, R.S. Anjum, R.M. Mohamed, M.B. Abuharb, B. Salah, M. El-Muraikhi, Production of sensitive gas sensors using CuO/SnO 2 nanoparticles, Applied Physics A, 125 (2019) 1-8. [3] A.I. Ayesh, S.T. Mahmoud, S.J. Ahmad, Y. Haik, Novel hydrogen gas sensor based on Pd and SnO2 nanoclusters, Materials Letters, 128 (2014) 354-357. [4] Schipper K., Al Muraikhi M., Alghasal G.S.H.S., Saadaoui I., Bounnit T., Rasheed R., Dalgamouni T., Al Jabri H.M.S.J., Wijffels R.H., Barbosa M.J., Potential of novel desert microalgae and cyanobacteria for commercial applications and CO2 sequestration, Journal of Applied Phycology, 2019 31:2231–2243. d a b f c e B 500mL culture 50mL culture Solid culture 1L culture 1 st subculture 3 rd subculture 2 nd subculture Subculture the biomass into media amended with different concentrations of SnO2 (1, 5, 25, 50 and 100mg/L) Algae cells Mixture Algae +SnO2 P. atomus SnO2 Nanoparticles SnO2 Algal Growth (OD 680nm) Metabolites analysis Morphological damages (SEM)