Toxic Effects of Silver Chitosan Nanocomposites on Aquatic Species

Anne Kahr^*
*Correspondence: Anne Kahr, Department of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Akadeemia Tee Tallinn, Estonia, Email:

Introduction

Silver–chitosan nanocomposites have gained attention in recent years due to their unique combination of properties, making them valuable in various applications, including water purification, medical devices and antimicrobial coatings. Silver Nanoparticles (AgNPs) are known for their strong antibacterial and antifungal properties, which are leveraged in these nanocomposites to enhance their effectiveness. Chitosan, a biopolymer derived from chitin, provides a matrix that stabilizes silver nanoparticles and adds additional antimicrobial properties. This combination aims to improve the functionality and stability of the nanoparticles compared to their use in isolation.

Despite their advantages, the environmental and ecological impacts of silver–chitosan nanocomposites are a growing concern. Aquatic ecosystems, which are sensitive to chemical pollutants and nanomaterials, might be adversely affected by the release of silver nanoparticles into water bodies. These particles can potentially disrupt aquatic life through various mechanisms, including bioaccumulation and toxicity. Understanding the extent of these impacts is crucial for assessing the overall safety and sustainability of silver–chitosan nanocomposites. This article provides a comprehensive review of the current research on the toxicity of silver–chitosan nanocomposites to aquatic species. It examines existing literature, discusses findings from various studies and highlights areas needing further investigation to ensure that the benefits of these materials do not come at the expense of environmental health [1].

Description

Background on nanocomposites

Nanocomposites combining silver nanoparticles and chitosan have emerged due to the need for advanced materials with enhanced performance and stability. Silver nanoparticles are renowned for their antimicrobial activity, which stems from their ability to release silver ions that interfere with microbial cell functions. Chitosan, a biopolymer obtained from chitin (a natural polymer found in crustacean shells), adds biocompatibility and additional antimicrobial effects to the nanocomposite. The synthesis of silver–chitosan nanocomposites involves various methods, such as chemical reduction, sol-gel processes and green synthesis approaches. These methods aim to optimize the size, distribution and stability of silver nanoparticles within the chitosan matrix. This synergy enhances the overall effectiveness of the material in applications like water treatment and medical devices.

Toxicity mechanisms

The toxicity of silver nanoparticles to aquatic species is primarily attributed to the release of silver ions into the water. These ions can interact with biological molecules, leading to oxidative stress, enzyme inhibition and cellular damage. Studies have demonstrated that silver nanoparticles can cause acute toxicity in various aquatic organisms, including fish, algae and invertebrates. Chitosan, while generally considered non-toxic and biocompatible, can influence the toxicity profile of silver nanoparticles. The polymer may affect the release rate of silver ions or modify their interaction with biological systems. In some cases, chitosan can mitigate the toxicity of silver nanoparticles by providing a protective matrix or altering the release dynamics of silver ions. However, the precise impact of chitosan on the overall toxicity of the nanocomposite can vary depending on its concentration, the size of the silver nanoparticles and the characteristics of the aquatic species exposed [2].

Previous studies

A variety of studies have explored the environmental impacts of silver nanoparticles and their combinations with other materials. Research has shown that silver nanoparticles can lead to significant toxicity in aquatic environments, affecting species such as zebrafish, Daphnia and various algae species. These effects include reduced growth rates, reproductive impairments and alterations in behavior. When silver nanoparticles are combined with chitosan, the results are not always straightforward. Some studies suggest that the chitosan matrix can reduce the overall toxicity by slowing down the release of silver ions or providing a barrier that limits direct contact with aquatic organisms. Conversely, other research indicates that chitosan might not significantly alter the toxicity profile or could even exacerbate certain effects under specific conditions. Overall, the literature reveals a complex relationship between the components of silver–chitosan nanocomposites and their environmental impact. The variability in findings underscores the need for further research to understand how these materials interact with different aquatic species and under various environmental conditions [3,4].

Comparing the toxicity of silver nanoparticles and silver–chitosan nanocomposites highlights the influence of the chitosan matrix on the overall environmental impact. While silver nanoparticles alone have been well-documented for their toxicity to aquatic life, the presence of chitosan can alter this toxicity in both positive and negative ways. In some cases, chitosan may reduce the toxicity by controlling the release of silver ions or modifying their interaction with biological systems. This can lead to a lower overall impact on aquatic species. However, the extent of this reduction depends on several factors, including the concentration of the nanocomposites, the size and form of the silver nanoparticles and the specific characteristics of the aquatic environment. On the other hand, certain studies have indicated that the combination of silver and chitosan does not significantly alter the toxicity profile compared to silver nanoparticles alone. In some instances, the presence of chitosan might even enhance the bioavailability of silver ions or interact with the biological systems of aquatic species in unforeseen ways [5].

Conclusion

Silver–chitosan nanocomposites offer significant potential due to their enhanced antimicrobial properties and versatility in various applications. However, their environmental impact, particularly on aquatic species, cannot be overlooked. The complexity of their toxicity profiles, influenced by both the silver nanoparticles and the chitosan matrix, necessitates further research to fully understand their effects and mitigate potential risks. Current literature indicates that while chitosan may modify the toxicity of silver nanoparticles, the outcomes are not always predictable and can vary depending on several factors. Therefore, continued investigation into the environmental fate, mechanisms of toxicity and long-term impacts of these nanocomposites is essential. By addressing these research gaps, we can ensure that the benefits of silver–chitosan nanocomposites are realized without compromising the health of aquatic ecosystems. Efforts to develop safer alternatives and improve our understanding of the environmental implications will contribute to more sustainable and responsible use of nanomaterials in various applications.

Acknowledgement

None.

Conflict of Interest

None.

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