A Mechanical Model for an Artificial Oocyte

Abstract

Abstract-Cell injection to introduce a foreign material in biological cells is currently an important area of research. Intervention with biological cells such as an oocyte poses a major limitation towards understanding their biomechanical behaviour, especially during injection, which could result in significant and undesirable deformation of the outer membrane. In this paper, a cross-linked alginate hydrogel is proposed as a material to develop an artificial oocyte to simulate the mechanical properties of a natural human oocyte and use it for mechanical analysis and modelling. A mechanical model and finite element analysis are first presented. The relationship between the injection force and the mechanical properties of the gel are then studied and presented. To validate the mechanical model, experiments were performed using different diameters of an oocyte made using the proposed hydrogel, showing that the modelling results satisfy the experimental demands and that this model can be used to estimate the mechanical properties of other gels too.Index Terms-Artificial oocyte, alginate, hydrogel, finite element model, deformation. I. INTRODUCTIONMany researchers have focused on micro-injection technology which has been proved to be an effective technique introducing foreign materials into cells. This technology can be applied for gene injection, In-vitro fertilisation (IVF), intra-cytoplasmic sperm injection (ICSI), drug development and other biomedical areas notably in cancer treatments [1]. To the best knowledge of the authors, this is the first report of proposing a material for fabricating an artificial oocyte.Accessing human biological oocyte samples for experimental work is very limited, and therefore having suitable artificial samples that could mimic the natural tissues would help to develop appropriate experimental methodology.Synthetic and natural polymers could be considered for the development of artificial tissues. In 2017 alginate hydrogels were proposed for transplantation of ovarian follicles considering different grafting times [2]. Alginate is one of the proposed materials which has the minimum grafting time that is reported to be one week [3]. Alginate

Loading equine oocytes with cryoprotective agents captured with a finite element method model

“…In addition to the balance of mass, one should take into account the equilibrium of mechanical forces that is governed by: where σ signifies the mechanical stress tensor defined in Eq. (17). It is apparent that, unlike Eq.…”

“…The finite element method (FEM) can be used to develop phenomenological simulations of mass transport and mechanical behavior in a 3D framework 14,15 . The FEM has been used to model the response of oocytes exposed to mechanical stress in a micromanipulator set up 16 , and to simulate mechanical properties of human oocytes 17 . The FEM subdivides a system into smaller parts (the finite elements) using spatial discretization leading to the emergence of a so-called mesh that represents the finite element problem.…”

The Role of MEMS in In-Vitro-Fertilization

“…During the ICSI process, the orientation of the oocyte cell plays an important role. This orientation should facilitate an obstacle-free path to the microneedle [32,48] during sperm injection. In the conventional ICSI process, this is carried out by collaboratively controlling the injection and holding pipettes.…”

“…farthest from the path of the injection needle (on the 6 or 12 O'clock position)[See Figure 5(b)], to protect the meiotic spindle[32], which is considered to be located in the boundary of the oocyte below the first polar body from being damaged. Subsequently, the equatorial plane of the oocyte is focused, and the injection pipette will be pressed against the zona pellucida [See Figure5(d)], creating a characteristic funnel, breaking the membrane, at 3 O'clock, at the approximate centre of the oocyte.…”

Simple bioelectrical microsensor: oocyte quality prediction via membrane electrophysiological characterization

“…Two such technologies that have gained traction within the medical research community are image processing and artificial intelligence techniques. 12,13 These tools can automate diagnosis and treatment procedures, as well as predict high-quality oocytes and embryos. By using image processing and artificial intelligence, the morphological characteristics of oocytes can be automatically analysed, enabling non-human entities to perform the duties of an embryologist.…”