Application of a modified NanoSuit method for SEM observation of diverse parasites: Toward integrative taxonomic analyses

Scanning electron microscopy (SEM) is a powerful tool for investigating the ultrastructure of small parasitic organisms. However, conventional SEM preparation requires labor-intensive, multistep procedures, namely chemical fixation, dehydration, drying, and metal coating, which induce shrinkage, deformation, or loss of delicate structures, particularly in minute parasites. The recently developed NanoSuit method enables SEM observation under high vacuum through the formation of a thin polymer membrane on the specimen surface that retains structural integrity and moisture. In this study, we applied a modified NanoSuit protocol to parasitic arthropods, nematodes, platyhelminths (aspidogastrids, digeneans, cestodes), protozoans (apicomplexans, ciliates), and myxozoans and systematically compared its performance with conventional preparation techniques. The modified method allowed high-resolution visualization of diagnostic morphological features with minimal deformation. All groups were successfully observed, with diagnostic morphological features clearly distinguishable. Additional advantages included a shorter preparation time, reduced specimen loss, and the possibility of reusing samples for light microscopy or DNA analysis after SEM observation. These findings demonstrate that the modified NanoSuit method provides a simple, versatile, and effective alternative to conventional SEM preparation, thereby expanding the methodological toolkit for integrative taxonomy in parasitology.