Ultrastructural Evaluation (SEM) of Ascaris lumbricoides Eggs Treated with Silver Nanoparticles Biosynthesised by Duddingtonia flagrans Using Scanning Electron Microscopy (SEM)

TL;DR

This study shows that silver nanoparticles made by a fungus can damage the tough eggs of a common intestinal worm, potentially improving treatments.

Contribution

The novel contribution is the use of AgNPs biosynthesized by Duddingtonia flagrans to induce structural damage in A. lumbricoides eggs.

Findings

AgNPs caused pronounced structural alterations in A. lumbricoides eggs, including wrinkling, erosion, and shell collapse.

Combined treatment with AgNPs and albendazole resulted in severe degradation of the egg structure.

AgNPs showed an IC50 of 7.7 µg/mL and could serve as adjuvants to conventional anthelmintics.

Abstract

Ascaris lumbricoides is one of the most epidemiologically significant soil-transmitted helminths, and the environmental persistence of its eggs is largely attributed to their robust structural architecture. The search for ovicidal alternatives capable of overcoming this barrier has increasingly focused on metallic nanoparticles obtained through biological synthesis. Scanning electron microscopy (SEM) was employed to evaluate the ultrastructural effects of silver nanoparticles (AgNPs) biosynthesised by the nematophagous fungus Duddingtonia flagrans on A. lumbricoides eggs. Ultraviolet-visible spectroscopy and transmission electron microscopy confirmed the synthesis of AgNPs, revealing predominantly spherical, well-dispersed particles with an average diameter of 9.22 ± 4.9 nm. Cytotoxicity assays indicated an IC50 of 7.7 µg/mL. SEM analyses showed that eggs in the control group maintained intact morphology, with no apparent deformities. In contrast, exposure to AgNPs induced pronounced structural alterations, including marked wrinkling, surface erosion and shell collapse, suggesting disruption of multiple layers. Albendazole alone produced deep linear fissures consistent with internal metabolic failure, though with minimal external erosion. The combined treatment with AgNPs and albendazole resulted in severe degradation. These findings demonstrate that AgNPs exhibit significant ovicidal activity and may serve as effective adjuvants to enhance the action of conventional anthelmintics against highly resistant helminth eggs.

Figures