Multiscale Experimental Evaluation of Agarose-Based Semi-Interpenetrating Polymer Network Hydrogels as Materials with Tunable Rheological and Transport Performance

Abstract

This study introduces an original concept in the development of hydrogel materials for controlled release of charged organic compounds based on semi-interpenetrating polymer networks composed by an inert gel-forming polymer component and interpenetrating linear polyelectrolyte with specific binding affinity towards the carried active compound. As it is experimentally illustrated on the prototype hydrogels prepared from agarose interpenetrated by poly(styrene sulfonate) (PSS) and alginate (ALG), respectively, the main benefit brought by this concept is represented by the ability to tune the mechanical and transport performance of the material independently via manipulating the relative content of the two structural components. A unique analytical methodology is proposed to provide complex insight into composition–structure–performance relationships in the hydrogel material combining methods of analysis on the macroscopic scale, but also in the specific microcosms of the gel network. Rheological analysis has confirmed that the complex modulus of the gels can be adjusted in a wide range by the gelling component (agarose) with negligible effect of the interpenetrating component (PSS or ALG). On the other hand, the content of PSS as low as 0.01 wt.% of the gel resulted in a more than 10-fold decrease of diffusivity of model-charged organic solute (Rhodamine 6G).

Novel Hydrogel Material with Tailored Internal Architecture Modified by “Bio” Amphiphilic Components—Design and Analysis by a Physico-Chemical Approach

“…Hydrogels with distinct gelation mechanisms (physical, ionic, chemical crosslinking) [ 20 ] were studied. As an example of a physically crosslinked matrix, the linear thermoreversible polysaccharide agarose (Agarose E, Condalab, Madrid, Spain) at 1 wt.%, was used [ 21 ]. As an example of an ionically crosslinked matrix, sodium alginate (Sigma-Aldrich, Prague, Czech Republic) at 2 wt.% crosslinked by calcium chloride (Lach-Ner, Neratovice, Czech Republic) at a two to one weight ratio was chosen [ 22 ].…”

“…The materials and their concentrations and ratios were selected on the basis of data previously reported [ 20 , 21 , 22 , 23 , 24 ] and can be seen in the table below ( Table 10 ).…”

Investigating the Kinetics and Structure of Network Formation in Ultraviolet-Photopolymerizable Starch Nanogel Network Hydrogels via Very Small-Angle Neutron Scattering and Small-Amplitude Oscillatory Shear Rheology

“…While a variety of methods including dynamic and static light scattering, , X-ray scattering, , turbidity/cloud point measurements, , and advanced electron microscopy methods − have been used for investigating the internal morphology of hydrogels, small-angle neutron scattering (SANS) is particularly useful given that both the pore size and the dimensions of typical gel inhomogeneities lie in the accessible SANS length scale (1–200 nm). − SANS is particularly useful for characterizing nanoparticle network hydrogels given that the mesh size of the nano/microgel, the mesh size between the nano/microgels, and the absolute size of the nano/microgels used all lie within the accessible SANS length scale (unlike with other methods) . SANS studies on preformed nano/microgel network hydrogels at an equilibrium swelling state have been reported both by our group and others. − Specific to SNPs and soluble starch, our previous SANS results suggested that SS hydrogels have significantly lower Porod exponents (corresponding to more Gaussian, swollen chains), significantly higher fluid correlation lengths (indicating larger gel mesh sizes), and much larger Lorentzian scales (indicating a significantly more fluid network structure) than SNP-based hydrogels.…”

Tailoring the Internal Microstructure of the Hydrogels Based on Poly-Hema Targeted for Drug Delivery Systems

“…The properties of hydrogels must vary according to the specific needs of individual applications, e.g., for drug delivery systems, suitable transport properties are crucial to their application. Recent studies [1][2][3][4] have focused on various strategies to improve these properties in hydrogels using a process such as the use of interpenetrating networks, composite structures, and dual crosslinking. Overall, hydrogel preparation methods that simultaneously mimic the hydration, strength, and stiffness of soft and supporting tissues have the potential to be used in a much wider range of biomedical applications.…”

“…Overall, hydrogel preparation methods that simultaneously mimic the hydration, strength, and stiffness of soft and supporting tissues have the potential to be used in a much wider range of biomedical applications. Using semi-interpenetrating polymer networks (semi-IPN) is a suitable way to modify the material properties by manipulation of the internal chemical and morphological architecture [2][3][4].…”