- In previous work, Massachusetts General Hospital researchers created a smartphone-based automated system that measures sperm concentration and motility
- With the addition of new algorithms, the system now measures sperm viability, DNA fragmentation and hyaluronic binding assay score as accurately as conventional methods
- Advantages of the modified system include its objectivity, speed, potential to be used in resource-poor settings and potential to facilitate research studies
Advances in technology have led to the development of an innovative tool for rapid, low-cost semen analysis at the point of care. In previous work published in Science Translational Medicine, John C. Petrozza, MD, director of the Fertility Center at Massachusetts General Hospital, collaborated with bioengineers to create a smartphone-based automated system that measures sperm concentration and motility.
Besides those basic parameters, other laboratory tests provide important information about the functionality of spermatozoa in cases of male factor infertility. The researchers, including reproductive endocrinology fellow Irene Dimitriadis, MD, and embryologist Charles Bormann, PhD, report in PLOS One that they improved their system to measure a hyaluronic binding assay (HBA) score, sperm viability and sperm DNA fragmentation.
Rationale for the Three Tests
- HBA test: quantitatively determines the overall sperm maturity status and fertilization potential in a semen sample. Currently, HBA analysis is performed manually using a laboratory-based microscope, which is labor-intensive
- Sperm viability test: can be used to approximate the proportion of viable sperm in a sample. However, a sperm viability test is required to distinguish immotile live sperm from dead sperm. Most methods of assessing sperm viability are based on the ability of the cell membrane to exclude dyes from entering the sperm and permeating into the nucleus. The eosin–nigrosin staining-based approach is one of the most commonly used
- A sperm DNA fragmentation test: measures the DNA damage present in a given sperm population, which has been correlated with both sperm motility and morphology. One of the most commonly used methods is a sperm chromatin dispersion test
Description of the System
Central to the smartphone-based system is an optical attachment, which consists simply of two lenses, a small battery, a switch and a white light-emitting diode. A slide holder aligns the lens set to the camera of a cell phone. The housing for the attachment was produced with a 3D printer. A disposable microfluidic device is also incorporated into the system.
For the modified version of the system, the researchers developed two applications, one designed to estimate the HBA score automatically and one that automatically assesses DNA fragmentation. The sperm viability assay relied on the eosin-nigrosin staining-based approach.
Testing the Modified System
In their latest study, the researchers conducted HBA, sperm viability and sperm DNA fragmentation tests using semen specimens discarded by patients undergoing routine fertility testing at Mass General clinics. The samples were measured using both the smartphone system and through traditional analyses (manual estimation for the HBA assay or standard benchtop microscopy for sperm viability and DNA fragmentation assays).
The smartphone-based system analyzed the specimens rapidly (in <1 minute). It identified abnormal samples with accuracies similar to those measured using conventional methods.
Advantages of the New System
- The automated analyses lend objectivity to what are usually subjective tests
- The speed of the analyses makes the workload of laboratory technicians less tedious, and faster turnaround might allow physicians and patients to make informed decisions in a single visit
- Because it is so inexpensive—the total cost of the optical hardware was less than $5—the smartphone-based approach may be useful in resource-limited settings
With the current form of the optical attachment, testing must be done by a laboratory technician. However, advances in microfluidics may allow the assays to be fully automated, the researchers say, making them usable at remote locations and by lay users.
The Future of Fertility Testing
12% of men will suffer from infertility during their lifetime, and the researchers believe smartphone-based semen analysis would be especially useful in research studies aimed at better understanding male infertility. They envision the devices being shipped to patients so they can perform their tests at home, then transmit the results to investigators using a cloud-based server. The optical attachment can be adapted easily to all existing smartphone models and does not require modifications to the smartphone's original system.
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