Structural analysis of dextran‐based hydrogels obtained chemoenzymatically

Abstract

This work reports the results of structural analysis in novel dextran-acrylate (dexT70-VA) hydrogels generated chemoenzymatically. Porous structure as well as hydrogel surface and interior morphologies were evaluated by mercury intrusion porosimetry (MIP), nitrogen adsorption (NA), and scanning electron microscopy (SEM) analyses, as a function of the degree of substitution (DS), and initial water content used in the preparation of the hydrogel. MIP analysis showed that the overall networks were clearly macroporous with pore sizes ranging from 0.065 to 10 microm. As expected, the average pore size decreased as DS increased and as initial water content decreased. Moreover, the porosity values ranged from 75 up 90%, which shows that these hydrogels present an interconnected pore structure. Nitrogen adsorption analyses showed that the specific surface area of dexT70-VA hydrogels increased either by increasing the DS or by decreasing the initial water content of the hydrogel. SEM results revealed that the surface of hydrogels with lower DS presented either a porous structure or a polymeric "skin" covering the pores, whereas hydrogels with higher DS were totally porous. Furthermore, the interior morphology varied according to the DS and the initial water content of the hydrogels. Finally, the average pore size was also determined from the swelling of hydrogel using a theoretical model developed by Flory-Rehner. The comparison of the SEM and MIP results with the ones obtained by the equilibrium swelling theory of Flory-Rehner shows that this approach highly underestimates the average pore size.

Surface area and pore structure properties of urethane-based copolymers containing β-cyclodextrin

“…In view of the substantial hydration and volumetric changes between an anhydrous copolymer and its hydrated state, the changes in hydration are anticipated to contribute significantly to their textural properties. Pronounced changes in the textural properties were observed in a recent structural study of dextran-based hydrogels by Ferreira et al [39]. The observed differences in the pore diameter of anhydrous gels were concluded from nitrogen adsorption and mercury intrusion porosimetry.…”

Photocrosslinkable Gelatin Hydrogel for Epidermal Tissue Engineering

“…Samples were then freeze-dried and weighed to determine the dry weight (W D ). The swelling ratio of the swollen gel (SR) was calculated according to Equation (1): [56] $$\mathrm{SR}=\frac{{\mathrm{normalW}}_{\mathrm{normalS}}-{\mathrm{normalW}}_{\mathrm{normalD}}}{{\mathrm{normalW}}_{\mathrm{normalD}}}\times 100\%$$…”

Reactive Maleimido Dextran Thin Films for Cysteine-Containing Surfaces Adsorbing BSA

“…However, the water uptake is not as high as in hydrogels or hydrophilic/zwitterionic films used for low‐fouling surfaces . Usually, the water content of cross‐linked dextrans based on methacrylate‐ or vinyl acetate is in the range from 60% up to >90% …”