Sperm Morphological Analysis Without Staining for Improved in Vitro Fertilization

Sperm cell morphology is analyzed for assessing the fertility potential of a male. Currently, it is performed by staining the cells with a dye, that creates a contrast between morphological features, such as the nucleus and the acrosome, and imaging it with a bright field microscope. Interferometric phase microscopy (IPM) is an imaging technique capable of capturing both amplitude and phase maps of transparent biological cells, and extracting the optical thickness of the cell. We demonstrate the use of IPM for imaging morphological features of sperm cells without staining. We compare images of cells obtained with IPM to images of the same cells obtained after staining, with bright field microscopy. We show that according to the WHO criteria for morphological analysis, IPM provides equivalent information to the current practice. Following, we show that we can extract the volume of cellular compartments, such as the acrosome, without staining. These initial findings may assist in selecting unstained sperm cells for in-vitro-cytoplasmic injection (ICSI) in the future, based on their morphological features.