# Robotic Manipulation of Cumulus-Oocyte Complexes for Cumulus Cell Removal
## 1 Introduction  
The removal of cumulus cells from cumulus-oocyte complexes (COCs) is a critical step before intracrotoplasmic sperm injection (ICSI), which is an infertility treatment used in around 70% of in vitro fertilization (IVF) cycles [1]. A COC is composed of an oocyte and the surrounding cumulus cells, which promote oocyte maturation [2]. However, cumulus cells block the injection micropipette during oocyte microinjection in ICSI. Moreover, the presence of cumulus cells also causes genetic contamination in the subsequent preimplantation genetic testing (PGT) due to the mixture of the target embryo and the non-target cumulus cells in the test sample [3, 4]. In manual cumulus cell removal, the COCs retrieved from ovarian follicles are first mixed with hyaluronidase to loosen the cumulus-oocyte bonds. The COCs are then transferred to M2 culture medium, and an embryologist manually removes cumulus cells by repeatedly aspirating and dispensing the COCs using a micropipette [5], as shown in Figure 1a. After cumulus cell removal, the mature oocytes with visible polar bodies are fertilized via ICSI and further cultured to blastocysts (i.e., day 5/6 embryos). Several trophectoderm (TE) cells are collected from the blastocysts for PGT, and blastocysts without genetic abnormalities are selected for the subsequent embryo transfer. In manual operations,embryologists remove cumulus cells without assessing the oocyte's maturity due to the occlusion of the polar body by the surrounding cumulus cells. The removal of cumulus cells before oocyte maturation may affect the maturation process and eventually result in maturation failure [6]. During cumulus cell removal, it is difficult to position the COC inside the micropipette, since the mass of the COC varies during aspiration. The COCs tend to move deeper into the micropipette and disappear, leading to the loss of COCs. Furthermore, since cumulus cells are small in size, it is difficult for embryologists to determine whether the cumulus cells have been completely removed from the oocyte. The remaining cumulus cells on the oocyte will lead to ICSI failure by blocking the injection micropipette, and they also reduce the PGT accuracy by introducing genetic materials different from the tested embryos, as shown in Figure 1b,c. There have been several emerging trends in robotics and automation in recent years. [PERSON] et al. integrated 3D digital twins into a collaborative robot, enabling robot joint visualization and automated control [7]. [PERSON] et al. proposed a virtual surrogate robot based on augmented reality technologies to automatically foreshadow the actions of a physical robot and improve the robot teleoperations [8]. [PERSON] et al. proposed a cyber-physical framework, which was capable of accomplishing automated assembly for micro-devices [9]. [PERSON] et al. used the zoom effect to deal with delay masking in order to remotely automate a robot through the Internet [10]. [PERSON] et al. developed a holographic optical tweezers-based platform to automatically manipulate organelles and characterize the mechanobiological properties of cells [11]. Robotic techniques are emerging in the areas of virtual robotics and physical robotics. Figure 1: **(a)** Manual operation for removing the cumulus cells from an oocyte. (b) The influence of cumulus cells in ICSI procedures. The remaining cumulus cells block the injection micropipette. (c) The influence of cumulus cells in PGT procedures. The DNA marker is used to distinguish the target band and the non-specific band by band size (i.e., 250 bp). The target band is formed from the embryonic DNA of TE cells, while the non-specific band is formed from the non-embryonic DNA of cumulus cells, causing contamination and reducing the PGT accuracy. Techniques have been developed to automatically remove cumulus cells. [PERSON] et al.