Dual polymer networks: a new strategy in expanding the repertoire of hydrogels for biomedical applications

Abstract

Inspired by the double network hydrogel systems we report the formulation of dual networks, which expands the repertoire of this class of materials for potential biomedical applications. The tough dual network hydrogels were designed through sequential interpenetrating polymer formation, applying green chemistry and low-cost methods, devoid of any initiator-activator complexes that may pose risks in biomedical applications. The dual networks were synthesized in two steps, firstly the water soluble poly(vinyl alcohol) was subjected to cryogelation that formed the first network, which was then expanded by intrusion of a dilute solution of sodium alginate and complexed with a solution of calcium chloride under ambient conditions and further freeze-thawed. These hydrogels are flexible, ductile and porous with the ability to absorb and retain fluids as well as possess the versatility to easily incorporate biological molecules/drugs/antibiotics to be applied in tissue matrices or drug delivery systems. The dual network hydrogels can be tailored to have varying mechanical properties, shapes, size, thickness and particularly can be made physically porous if required, to suit the users intended application.

Glibenclamide Nanocrystal-Loaded Bioactive Polymeric Scaffolds for Skin Regeneration: In Vitro Characterization and Preclinical Evaluation

“…Despite the increase in porosity achieved following NC-GL loading in scaffolds with a total polymer content of 3% w/v, NC-GL might have provided a longer water diffusion path, hindering the loosening of polymeric chains and resulting in a lower swelling percent [75]. In addition, the lower SI of the loaded scaffolds could be attributed to the lower hydrophilicity of NC-GL relative to the polymers used [76] and the possibility of mechanical interlocking between polymeric chains created by incorporation of NC-GL [64,77], where NC might have acted as an additional physical crosslinker preventing water absorption [75].…”

Dual Network Composites of Poly(vinyl alcohol)-Calcium Metaphosphate/Alginate with Osteogenic Ions for Bone Tissue Engineering in Oral and Maxillofacial Surgery

“…A new class of composite material based on dual network system [ 11 ] containing osteogenic ions of Ca 2+ , Zn 2+ and Sr 2+ was successfully developed. 13 C-NMR, FTIR and Raman spectra of DNC-Ca, Zn and Sr demonstrated distinct broadening, shifting and peak intensity.…”

“…We earlier reported tough interpenetrating polymer network systems, referred to as dual networks (DN) [ 11 ] similar to double networks (DbN) [ 12 ]. The DN’s were formed using water-soluble polymers of poly(vinyl alcohol) (PVA) and alginate crosslinked via freeze–thawing (FT) of PVA and calcium salt solution chelation without incorporation of toxic solvents, initiators, activators and crosslinking agents.…”

“…The first network of the PVA-alginate DN was formed by FT of PVA solution and subsequently swollen in sodium alginate solution chelated with calcium chloride to form the second network. DN resulted in greater mechanical strength, toughness and ductility than its each polymer constituent due to the interpenetration of rigid alginate network into the PVA matrix, which increased the network density and stiffness, and the ability of the alginate network to break early and dissipate the energy, preventing rapid fracture growth [ 11 ]. Since divalent cations can be used to effect chelation of sodium alginate, osteogenic ions such as Ca 2+ , Zn 2+ and Sr 2+ were used to incorporate trace amounts of these ions in the PVA-CMP SNC.…”

Influence of photooxidation on ionic reversible interactions of ionic poly(ether urethane)/silica hybrids

“…Dynamic polymeric materials, whereby specific bonds or interactions can undergo reversible breaking and restoration under certain conditions have gained significant attention and opened up new pathways for the design of tunable adaptive materials [1][2][3]. Among these dynamic polymer systems, ionic materials leverage the dynamic and reversible nature of electrostatic bonding by maximizing Coulomb interactions in the system [4][5][6]. Building on ionic motifs, Yuan et al recently designed ionic hydrogels made of a mixture of two polycations and two polyanions of different acid dissociation constant, resulting in unique mechanical performance (i.e.…”