Infertility is a prevalent global health concern affecting one in six individuals [1], with male infertility contributing to about 45% of these cases [2]. Over the past four decades, assisted reproductive technologies (ART) have emerged to combat infertility. A key step in ART is the selection of high-quality sperm, which significantly impacts the treatment’s success rate, live-birth rate, and offspring health [3]. However, current clinical sperm selection methods are largely manual, time-intensive, susceptible to operator errors and differ considerably from natural three-dimensional (3D) in vivo selection. Conventional methods have not been changed over the past 40 years, resulting in limited success rates for treatment cycles [4]. Here, we present a scalable, high throughput, and clinically relevant technology for selecting high-quality sperm via a 3D network of microchannels.
The 3D platform of the sperm selection device mimics the highly parallelized and 3D structure of the female reproductive tract and allows for high-throughput selection. The device was initially fabricated using a rapid prototyping method (3D printer) [5]. However, to facilitate clinical translation, the device design has been modified for injection moulding. Subsequently, a novel prototype composed of polystyrene was developed. During the selection time, motile sperm navigate through the microchannels to reach the outlet, while debris and non-motile cells are retained in the inlet. The selection throughput of the device is over 41%, significantly higher than previously developed microfluidic technologies. It retrieves over 1.6 million high-quality sperm in just 15 minutes which is more than sufficient for applications in IVF and IUI. Furthermore, the results indicated over 65% improvement in both DNA integrity and morphologically normal sperm.
In conclusion, we present a low-cost and rapid selection method, offering a promising possibility for conducting IUI and IVF procedures more frequently in fertility clinics.