Toxicity Effect of Silver Nanoparticles on Photosynthetic Pigment Content, Growth, ROS Production and Ultrastructural Changes of Microalgae Chlorella vulgaris

Layla J Hazeem,Mohamed Bououdina,Alexandre Barras,Rabah Boukherroub,Christian Slomianny,Gamze Kuku,Mustafa Culha,Etienne Dewailly,Abderrahmane Hamdi

doi:10.3390/nano9070914

Abstract

Silver nanoparticles (Ag NPs) exhibit antibacterial activity and are extensively used in numerous applications. The aim of this study was to examine the toxic effect of Ag NPs on the marine microalga, Chlorella vulgaris. The microalgae, at the exponential growth phase, were treated with different concentrations of Ag NPs (50 and 100 nm) for 96 h. X-Ray diffraction (XRD) results indicated that the used NPs are single and pure Ag phase with a mean crystallite size of 21 and 32 nm. Ag NPs were found to have a negative effect on viable cell concentration, a variable effect on chlorophyll a concentration, and increased ROS formation. Transmission electron microscopy (TEM) analysis revealed that Ag NPs were present inside the microalgae cells and formed large aggregates in the culture medium. Ag+ ions, in the form of AgNO3, were also assessed at higher concentrations and found to cause inhibitory effects.

Highlights

Silver nanoparticles (Ag NPs) are extensively used in numerous applications [1]; they are employed in more than two hundred customer manufactured goods, including deodorants and socks [2]
Due to their antibacterial and antiviral properties [3,4], they are utilized for medical purposes, employed in many engineered products, and were added to detergents as dynamic compounds [5,6,7,8,9]. They already have applications in personal care products, food storage boxes, laundry, domestic devices, paints, as well as cooking additives [10]. They can be combined with other materials to demolish harmful algal blooms—for instance, by employing TiO2 semiconductors functionalized with Ag NPs [11]
It is significantly important to point out that Ag NPs are produced in different sizes and will have diverse molecular reactivity properties depending on their surface-area-to-mass ratio [13]

Summary

Introduction

Silver nanoparticles (Ag NPs) are extensively used in numerous applications [1]; they are employed in more than two hundred customer manufactured goods, including deodorants and socks [2] Due to their antibacterial and antiviral properties [3,4], they are utilized for medical purposes, employed in many engineered products, and were added to detergents as dynamic compounds [5,6,7,8,9]. They already have applications in personal care products, food storage boxes, laundry, domestic devices, paints, as well as cooking additives [10] They can be combined with other materials to demolish harmful algal blooms—for instance, by employing TiO2 semiconductors functionalized with Ag NPs [11]. It is significantly important to point out that Ag NPs are produced in different sizes and will have diverse molecular reactivity properties depending on their surface-area-to-mass ratio [13]

Objectives

Methods

Results

Conclusion