Modeling the controllable pH-responsive swelling and pore size of networked alginate based biomaterials

Tailoring pH-responsive acrylic acid microgels with hydrophobic crosslinks for drug release

“…Specifically, by increasing the crosslinking density (EGDMA content) the rate, as well as the amount, of hydrophobic dye released is reduced. This was expected, since by increasing the crosslinking density the mesh/pore size of the microgels decreases 43,44 so it is more difficult for the dye to diffuse out. In addition, by increasing the EGDMA (crosslinker) content, which is itself hydrophobic, the hydrophobic dye will be retained in the microgel structure to a great extent due to van der Waal's interactions.…”

How the structural and physicochemical properties of polyacrylamide/alginate hydrogel influence its oxygen permeability

“…The free water refers to the water molecules which have not any hydrogen bonds with the polymer matrix and so have the thermodynamic behavior of pure water (freezing at 273 K). Based on the difference in freezing/ melting temperatures of adsorbed water, several analytical methods were developed which allow determining such parameters as the apparent porosity [21,25] and the amount of "free" water [13].…”

Soft nanofluidics governing minority ion exclusion in charged hydrogels

“…This asymmetry between the distribution of co-and counter-ions is known to be 50 associated with high fixed local space charge, 12 and it implies that it may be suitable to use the Gibbs-Donnan model for properties related to majority ionic species, under conditions not necessarily compatible with the basic assumption of homogeneous space charge distribution. For instance, the osmotic pressure within the 55 gels is a crucial element in the understanding of hydrogel swelling within the Flory-Huggins theory 17 , where it is successfully evaluated using the Gibbs-Donnan model modified for counter-ion condensation, but only with minor activity coefficient corrections 17 .…”

“…While some hydrogels, namely polyacrylates with a 5 very high monomer concentration do have such small pores, 16 the diameter in typical protein or carbohydrate hydrogels is in the range of 10nm to 1µm and sometimes beyond. [17][18][19][20] We investigate here how ionic partition in alginate gels with a pore size in the range of 10-40nm should be modeled : Either by 10 the use of the Gibbs-Donnan equilibrium, assuming homogeneous space distribution due to a hypothetical infinitely high chain mobility? Or by the use of the Poisson-Boltzmann equations, assuming a static gel structure?…”