סמינר המחלקה להנדסה ביו רפואית

דר' מיקי הייפלר

ירצה בנושא:

Interferometric phase microscopy for morphological sperm cell evaluation

Following the introduction of in-vitro fertilization (IVF), extensive research was conducted on the ability of sperm cell morphology to predict the success rates of natural fertilization, intra-uterine insemination, IVF and IVF with intra-cytoplasmatic sperm injection (ICSI). Typically, sperm cells are imaged optically using bright-field microscopy (BFM) and chosen according to the world health organization (WHO) guidelines. New methods were developed for identifying finer properties of the sperm cell, not seen by BFM but most of these methods involve biochemical preparations that might change the viability of the cells and thus precluding their use in IVF.

Without staining, sperm cells are nearly transparent under BFM, since their optical properties are only slightly different from their surroundings, resulting in a weak image contrast. An internal contrast mechanism when imaging sperm cells is their refractive index. The light beam that passes through the sperm cells is delayed, since the cells have a slightly higher refractive index compared to their surroundings.

Interferometric phase microscopy (IPM) is a holographic imaging method, which allows for a fully quantitative measurement of the cell optical thickness (i.e. the product of refractive index and physical thickness) on all the sperm spatial points. Recently, we have developed a portable and easy to operate IPM module, which can attach to existing clinical microscopes and provide label-free, quantitative contrast for cell samples.

In this study, we compared IPM with BFM in evaluating sperm cell morphology. Second, we used IPM to identify finer properties of sperm cell morphology and compared it to differential interference contrast microscopy, which is another phase imaging method used for sperm cell selection. Finally, we identified novel markers based on IPM that can predict the normality of sperm cell morphology.