Application of open porous poly(D,L‐lactide‐co‐glycolide) microspheres and the strategy of hydrophobic seeding in hepatic tissue cultivation

Abstract

In this article, porous poly(D,L-lactide-co-glycolide) (PLGA) microsphere scaffolds with a size of ∼ 400 μm and pores of ∼ 20 μm were prepared for constructing injectable three-dimensional hepatocyte spheroids. The porous sites of PLGA microspheres provided a spatial space for hepatocyte distribution. Hepatocytes spheroids were cocultured with human umbilical vein endothelial cell, bone marrow mesenchymal stem cell, or NIH/3T3 cells by combining the porous PLGA microspheres with the relatively hydrophobic culture strategy. The combination of open porous microspheres, hepatocytes, and nonparenchymal cells was demonstrated for application in functional hepatic tissue reconstruction. Hepatocellular-specific functions can sustained up to 2 weeks in the support of coculturing with nonparenchymal cells. The spheroidal hepatocyte coculture system had the advantages of an injectable delivery, higher cell seeding density, protection from exerted shear stress, better exchange of nutrients, oxygen and metabolites, and heterotypic cell-cell contact within and between microspheres.

Suspended polyhydroxyalkanoate microspheres as 3D carriers for mammalian cell growth

“…Small pores of approximately 1-3 lm in size were found located in the vicinity of these large pores. Similar open porous structures of microspheres made from PLGA and PLA were reported [32][33][34][35]. Yet this study was the first successful attempt to prepare PHA (PHBVHHx) PMSs.…”

“…Both spherical and confluent cell morphologies on PLGA open and highly porous microspheres were reported without cell viability study using either MTT or CCK-8 [32,33]. The spherical cells may not be healthy enough as acid products from PLA or PLGA degradation could lower the surrounding pH.…”

“…The interconnected porous structure can not only enlarge the surface and internal areas, but also facilitates in-and out-transport of nutrients and metabolites for subsequent cell proliferation and differentiation [30,31]. A highly open porous microsphere based on PLGA were reported prepared using a modified double emulsion solvent evaporation method [32][33][34][35]. The method replaces other aqueous phase with ammonium bicarbonate aqueous solution, which releases ammonia and carbon dioxide as a pore-foaming agent after emulsification.…”

Advances in multicellular spheroids formation

“…PLG has been used in different forms such as foam, fibres and sponges [100]. A porous PLG microsphere scaffold was developed to culture hepatocyte spheroids [84]. This approach accelerated MCS formation and the porous scaffold structure maximized cell attachment and transportation of nutrients, oxygen and wastes.…”

“…cell [82] synthesized polymers PEG -good biocompatibility -irreversible gelation leading to challenges in releasing MCSs from gel Huh7.5 cells [12], submadibular glands [83] PLG/PLGA -biodegradable and biocompatible hepatocytes [84], MCF-7, U87 [49] NIPAM-based hydrogel -thermally reversible to release MSCs during harvest -low viscoelasticity -porous structure with great nutrient, oxygen and waste transport HepG2 [85], HeLa [51], human pluripotent stem cells [7] poly(1-carpolacton)…”