Sex Selection Technology
Engender’s technology is a sort-on-a-chip approach with integrated microfluidic and photonic components. Engender’s design is expected to achieve high efficiency and high accuracy sperm sex selection with increased viability and therefore increased expected fertility. The chip based approach will allow for highly parallel processing to achieve high throughput, higher cell counts to improve fertilization, and higher purity to improve sperm sex selection. The new chip and instrument is expected to have a ~10 fold less capital cost than the current technology, which requires a dedicated laboratory plus capital equipment.
Engender’s design is expected to achieve high efficiency and high accuracy sperm sex selection with increased viability and therefore increased expected fertility.
Sorting sperm by sex is a challenge as the external differences between male (Y chromosome) and female (X chromosome) bearing sperm cells of sperm are minimal. Y- and X-bearing sperm exhibit very similar characteristics of motility, swimming speed, size, density, shape, surface protein description, and other physical and chemical characteristics. Sex-based differences are so small that they are overwhelmed by the width of the distribution for each sex. The most reliable known method of identifying the sperm that will lead to female (or male) offspring is to measure the sperm’s DNA content. The Y chromosome, which results in male offspring, is slightly smaller than the X chromosome, which results in female offspring. Therefore, the most known reliable sorting methods are based on identification of the total DNA content within sperm; the DNA content is a few percent greater in X-bearing sperm than in Y-bearing sperm. Once the sperm is identified as X- or Y-bearing, the sperm can be physically separated into different containers.
In Engender’s technology, this separation is achieved by moving sperm from one flow stream in a microfluidic chip into another using a pulse of light. The force required to move the sperm is small, and therefore the interaction between the pulse of light and the sperm cell is very gentle. To increase the final fraction of X-bearing or Y-bearing sperm with minimal sacrifice in total healthy cell count, multiple sorting steps can be easily deployed on a single chip. Importantly, the reduction in shear stress and the absence of an electric field as the sorting method are what makes Engender’s technology less detrimental to the health of the sperm, in comparison to the only currently available technology
Should Engender’s microfluidic system be commercially proven, it will significantly increase the viability of and reduce the cost of sexed semen, which Engender believes would stimulate widespread uptake.
Despite the advantages of sexed semen to the industry, the growth in the sexed sperm market appears to have been slow due to the high costs and reduced fertility rates of the current technology.
The only existing technology with the ability to sort sperm by sex uses flow cytometry. This method of separation reliably shows the ability to select X-bearing sperm at greater than 90% purity. To achieve this high purity, a large fraction of healthy sperm cells are discarded, reducing the overall sperm count available per ejaculate. The high capital and operating cost of flow cytometer devices and their low throughput result in sexed semen straws that are ~4x the cost of unsexed semen straws. We expect Engender's method of sorting sperm will lead to substantially higher fertility in sex-sorted sperm, even on animals in their conception prime years (heifers for dairy artificial insemination).
Should Engender’s microfluidic system be commercially proven, Engender believes it will significantly increase the viability of and reduce the cost of sexed semen, which Engender believes would stimulate widespread uptake. US academic Professor George Seidel has estimated that in the US, high quality sexed semen would be worth an additional US$23-67 per dose to dairy producers.