Three-dimensional systems for in vitro follicular culture: overview of alginate-based matrices

Abstract

The in vitro culture of ovarian follicles has provided critical insight into the biology of the follicle and its enclosed oocyte and the physical interaction and communication between the theca and granulosa cells and the oocyte that is necessary to produce meiotically competent oocytes. Various two-dimensional (2D) and three-dimensional (3D) culture systems have been developed to evaluate the effect of growth factors, hormones, extracellular matrix components and culture conditions on follicle development and oocyte growth and maturation. Among these culture systems, 3D systems make it possible to maintain follicle structure and support communication between the various cell compartments within the follicle. In this review article, we will discuss the three main approaches to ovarian follicle culture: 2D attachment systems, 3D floating systems and 3D encapsulated systems. We will specifically emphasise the development of and advances in alginate-based encapsulated systems for in vitro follicle culture.

Alginate Matrix of MDA-MB-231 Breast Cancer Cell 3D Culturing Alters CD44 and CD24 mRNA Levels and Induces ALDH1 Expression

“…Alginate matrix modulates and supports several biological processes, including the transport of bioactive agents, such as growth factors and hormones [32,33]. Other natural polymers can contain proteins and extracellular matrix components, as well as polysaccharides obtained from other biological sources, such as agarose and chitosan [25,39]. Alginate is an inert material and it still allows a cell culture without medium alteration serving as a scaffold.…”

“…Comparing to synthetic hydrogels, both are biologically inert. Synthetic polymers such as PEG (polyethylene glycol), PGA (polyglycolic acid) and PVA (polyvinyl alcohol) are excellent in terms of mechanical and hydrophilic properties [36], but they require addition of molecules to be functional and some of them do not support remodeling of growing cells [25]. This feature can impair cellular responses Regarding to cell culture model, the alginate matrix has been used as a scaffold to human stem cells in vitro culturing.…”

“…They found that cells were viable and spread in both 2% alginate and 0.5% in alginate-RGD (arginine-glycine-aspartic acid peptide-contains cell adhesion ligands) hydrogels during 6 days. Once alginate derived from natural source, it exhibits an inherent biocompatibility [37] and is also physicochemically well defined to provide a stable culture system without interfere with cellular functions [25,38]. Alginate matrix modulates and supports several biological processes, including the transport of bioactive agents, such as growth factors and hormones [32,33].…”

“…This may influence the outcome of expression of tumor stem cell breast markers. It is also important to consider that 3D culture model performed does not require supplementation of culture media with growth factors or insulin, which is normally used in spheroids, as also has not a deposited matrix, such as collagen or agar [25]. Thus, it is permissible to consider that the result reflects the MDA-MB-231 cell behavior in culture model and suggests that the method by itself is capable of inducing the change of gene expression stem cell markers, not observed in monolayer culture.…”

“…Additionally, alginate has intrinsic biocompatibility and capacity for forming gel with well-defined features, such as size and density [25] and moreover, it mimics the extracellular matrix or basal membrane to support cell functions and metabolism [26].…”