Paper-Based Test May Increase Male Fertility Self-Testing

Apaper-based assay can provide quantitative measurement of live and motile sperm concentrations and motility, in only 10 minutes, according to a study published online Jan. 8 in Clinical Chemistry. This approach, the authors say, is as accurate as laboratory-based methods and could promote over-the-counter self-diagnostic testing among men, embarrassed to seek clinical testing.

The authors say that up to half of infertility globally is caused by male factors. They believe this paper-based microfluidic test can improve upon costly and complex conventional testing (counting chambers, computer-assisted sperm analysis [CASA], and vitality assays such as dye exclusion or hypotonic swelling), as well as existing commercially available home microfluidic-based semen analysis tests— which are hampered by prolonged multistep processing, lack of quantification, reliance on the end-user interpretation, and measurement of only one semen parameter.

The authors say the simple design and fabrication make the test low cost, with total material costs of approximately $0.05 per device.

"All these current semen analysis techniques suffer from limitations that prevent their widespread application: testing procedures are long and complex and require expensive equipment, and the results are subjective, varying from clinician to clinician. … A low-cost and rapid test for semen analysis, suitable for both clinical and self-diagnosis, would have substantial implications for patient care, write the authors led by Reza Nosrati, from University of Toronto in Canada. "Our paper-based technology is an attractive alternative to conventional laboratory testing, with additional potential for self-screening of male fertility potential."

This paper-based device (multilayer porous composite) measures the diaphorase flavoprotein enzyme (present in metabolically active human sperm) through colorimetric change of yellow tetrazolium dye to purple formazan to quantify live and motile sperm concentration. A detectable color change on the readout indicates sufficient fertility potential. Optimal operating parameters include 4-mm diameter reaction spots, 3-μL sample volume, and 10-minute reaction time.

Fresh human semen samples from five patients and 12 healthy donors were analyzed using the paper-based assay as well as a conventional CASA system for concentration and motility, and a dye exclusion assay for sperm vitality.

The researchers found the paper-based assay had detection limits of 8.46 and 15.18 million/mL for live and motile sperm concentrations, respectively. The live and motile sperm concentrations and motility values correlated 100 percent with those of the standard clinical approaches. Additionally, the device was determined to be so robust and could tolerate conditions of high absolute humidity (22.8 g/m3) for up to 16 weeks when packaged with desiccant.

The authors say the simple design and fabrication make the test low cost, with total material costs of approximately $0.05 per device. Sinton tells DTET that his group is conducting further validation in partnership with a leading urology lab and fertility clinic. He is aiming for either direct commercialization and/or licensing that will make products available in the next few years.

Takeaway: A paper-based assay capable of measuring three common sperm parameters in a self-test format could substantially impact care for male fertility.