Interferometric phase microscopy for label-free morphological evaluation of sperm cells

Area of Science:

• Reproductive biology and andrology.
• Optical microscopy techniques.
• Medical diagnostics.

Background:

• Sperm morphology assessment is crucial for male fertility evaluation.
• Traditional methods often require staining, which can alter cell characteristics.
• Label-free microscopy offers a potential alternative for unstained sperm analysis.

Purpose of the Study:

• To compare the efficacy of label-free interferometric phase microscopy (IPM) with both label-free and label-based bright-field microscopy (BFM) for sperm morphology evaluation.
• To assess the potential of IPM as a non-staining method for clinical sperm analysis.

Main Methods:

• A comparative study involving 350 sperm cells from healthy donors.
• Evaluation using portable IPM and BFM against World Health Organization (WHO) criteria.
• Analysis of sperm head and midpiece dimensions, acrosome size, and overall cell morphology.

Main Results:

• IPM showed no statistical difference compared to label-based BFM for WHO criteria.
• IPM measurements of sperm head/midpiece width and acrosome area differed from label-free BFM.
• IPM demonstrated higher sensitivity and specificity than label-free BFM for WHO criteria.

Conclusions:

• Label-free IPM effectively identifies sperm abnormalities with high correlation to label-based BFM.
• IPM exhibits superior accuracy compared to label-free BFM in sperm morphology assessment.
• Further clinical trials are needed to integrate IPM into sperm selection procedures.