Spermatozoa quality assessment: a combined holographic and Raman microscopy approach

Abstract

Semen analysis is widely used as diagnostic tool for assessing male fertility, controlling and managing the animal reproduction. The most important parameters measured in a semen analysis are the morphology and biochemical alterations. For obtaining such information, non-invasive, label-free and non-destructive techniques have to be used. Digital Holography (DH) combined with Raman Spectroscopy (RS) could represent the perfect candidate for a rapid, non-destructive and high-sensitive morphological and biochemical sperm cell analysis. In this study, DH-RS combined approach is used for a complete analysis of single bovine spermatozoa. High-resolution images of bovine sperm have been obtained by DH microscopy from the reconstruction of a single acquired hologram, highlighting in some cases morphological alterations. Quantitative 3D reconstructions of sperm head, both normal and anomalous, have been studied and an unexpected structure of the post-acrosomal region of the head has been detected. Such anomalies have been also confirmed by Raman imaging analysis, suggesting the protein vibrations as associated Raman marker of the defect.