Combined Raman and polarization sensitive holographic imaging for a multimodal label-free assessment of human sperm function

Abstract

Raman microspectroscopy (RM) and polarization sensitive digital holographic imaging (PSDHI) are valuable analytical tools in biological and medical research, allowing the detection of both biochemical and morphological variations of the sample without labels or long sample preparation. Here, using this multi-modal approach we analyze in vitro human sperm capacitation and the acrosome reaction induced by heparin. The multimodal microscopy provides morphofunctional information that can assess the sperms ability to respond to capacitation stimuli (sperm function). More precisely, the birefringence analysis in sperm cells can be used as an indicator of its structural normality. Indeed, digital holography applied for polarization imaging allows for revelation of the polarization state of the sample, showing a total birefringence of the sperm head in non-reacted spermatozoa, and a birefringence localized in the post-acrosomal region in reacted spermatozoa. Additionally, RM allows the detection and spectroscopic characterization of protein/lipid delocalization in the plasma and acrosomal membranes that can be used as valuable Raman biomarkers of sperm function. Interestingly, these spectral variations can be correlated with different time phases of the cell capacitation response. Although further experimentation is required, the proposed multimodal approach could represent a potential label-free diagnostic tool for use in reproductive medicine and the diagnosis of infertility.

Raman Microscopy: Progress in Research on Cancer Cell Sensing

“…When using two orthogonally polarized reference waves, it possible to reconstruct not only morphology information but also intrinsic information about the polarization state of the sample through the phase change quantification [ 60 ]. Indeed, it has been observed that cells/tissues are composed of regularly arranged protein filaments that may affect their birefringence behavior [ 61 ].…”

Label-free imaging and analysis of subcellular parts of a living diatom cylindrotheca sp. using optical diffraction tomography

“…For the last decade, there have been significant developments in the instrumentations of QPI. [2,7,[11][12][13][14][15][16][17] For example, the spatial and temporal resolution of QPI had been improved and reached the limitations of farfield diffraction resolution and the speed of a high-speed image sensor. [18][19][20][21][22] Recently, many researchers have intensively reported biological applications of QPI, in particular, medical applications.…”

Classification and Identification of Archaea Using Single-Cell Raman Ejection and Artificial Intelligence: Implications for Investigating Uncultivated Microorganisms

“…Cells of both H5 and H7 contain pigments, such as retinal proteins cruxrhodpsin-2 and bacterial rhodopsin. Additionally, all halophilic archaea (H1–H7) have an apparent significant Raman band at around 893 cm –1 which can be assigned to glycoproteins. , Halophilic archaea usually accumulate large amounts of monosaccharides, glycerol, and other small molecule polarizers in cells, which are used to constitute penetration regulators rapidly …”

“…Additionally, all halophilic archaea (H1−H7) have an apparent significant Raman band at around 893 cm −1 which can be assigned to glycoproteins. 34,35 Halophilic archaea usually accumulate large amounts of monosaccharides, glycerol, and other small molecule polarizers in cells, which are used to constitute penetration regulators rapidly. 36 The SCRS of SCM1 show a distinct Raman band at 1044 cm −1 (Figure 1), which is contributed by the γ1 symmetric stretch in sodium bicarbonate.…”