UNASSIGNED: Polymeric microspheres may serve as microcarrier matrices, for the expansion of anchorage-dependent stem cells. They require surface properties that both promote initial cell adhesion and the subsequent spreading of cells, which is a prerequisite for successful expansion. When implemented in a three-dimensional culture environment, under @entity2146 , their suspension under low shear rates depends on the microcarriers having a modest negative buoyancy, with a density of 1.02-1.05 g/cm(3). Bioresorbable @entity4351 ( @entity4351 ), with a density of 1.14 g/cm(3), requires a reduction in volumetric density, for the microspheres to achieve high cell viability and yields. Uniform-sized droplets, from solutions of @entity4351 dissolved in @entity1044 ( @entity17058 ), were generated by a coaxial microfluidic geometry. Subsequent exposure to @entity1068 rapidly extracted @entity17058 solvent, solidifying the droplets and yielding monodisperse microspheres with a porous structure, which was demonstrated to have tunable porosity and a core-shell configuration. The variation of process parameters, including the molecular weight of @entity4351 , its concentration in @entity17058 , and the @entity1068 concentration, served to effectively alter the diffusion flux between @entity1068 and @entity17058 , resulting in a broad spectrum of volumetric densities of 1.04-1.11 g/cm(3). The solidified microspheres are generally covered by a smooth thin skin, which provides a uniform cell culture surface and masks their internal porous structure. When coated with cationic polyelectrolyte and extracellular matrix protein, monodisperse microspheres with a diameter of approximately 150   m and densities ranging from 1.05-1.11 g/cm(3), are capable of supporting the expansion of @entity1 mesenchymal stem cells (hMSCs). Validation of hMSC expansion was carried out with positive control of commercial Cytodex 3 microcarriers and negative control of uncoated low-density @entity4351 microcarriers. Static culture conditions generated more than 70% cell attachment and similar yields of 6-fold cell expansion on all coated microcarriers, with poor cell attachment and growth on the negative control. Under @entity2146 , coated porous microspheres, with a low density of 1.05 g/cm(3), achieved robust cell attachment and resulted in high cell yields of 9-fold cell expansion, comparable to those generated by commercial Cytodex 3 microcarriers.

Tunable Volumetric Density and Porous Structure of Spherical Poly-  -caprolactone Microcarriers, as Applied in XXXX Mesenchymal Stem Cell Expansion.

@entity1 :: ('9606', 'Species') :: ['human'] @entity1044 :: ('MESH:D008752', 'Chemical') :: ['dichloromethane'] @entity17058 :: ('CHEBI:15767', 'Chemical') :: ['DCM'] @entity4351 :: ('CHEBI:60736', 'Chemical') :: ['polycaprolactone', 'PCL'] @entity2146 :: ('MESH:D011595', 'Disease') :: ['agitation'] @entity1068 :: ('MESH:D000431', 'Chemical') :: ['ethanol']
@entity1 :: (9606,Species) :: ['Human']
