Advanced biomedical hydrogels: molecular architecture and its impact on medical applications

Abstract

Hydrogels are crosslinked polymeric networks swollen in water, physiological aqueous solutions, or biological fluids. They are synthesized by a wide range of polymerization methods that allow for the introduction of linear and branched units with specific molecular characteristics. In addition, they can be tuned to exhibit desirable chemical characteristics including hydrophilicity or hydrophobicity. The synthesized hydrogels can be anionic, cationic, or amphiphilic, and can contain multifunctional crosslinks, junctions or tie points. Beyond these characteristics, hydrogels exhibit compatibility with biological systems, and can be synthesized to render systems that swell or collapse in response to external stimuli. This versatility and compatibility have led to better understanding of how the hydrogel’s molecular architecture will affect their physicochemical, mechanical, and biological properties. We present a critical summary of the main methods to synthesize hydrogels which define their architecture, and advanced structural characteristics for macromolecular/biological applications.

Bioinspired Hydrogels as Platforms for Life-Science Applications: Challenges and Opportunities

“…Gelation and network formation can be induced in different ways, either through chemical, physical, or combined crosslinking, as it was discussed in recent comprehensive reviews [1,2,4,[18][19][20]30,[55][56][57][58][59][60]. The characteristics of the building blocks influence in high extent the physico-chemical, mechanical, and biological properties of the hydrogels.…”

“…Researchers are looking in nature for inspiration for developing functional hydrogels with controlled structure and tuned properties in order to satisfy the increasing demands of practical applications. To achieve these requirements, a combination of self-assembly, chemical crosslinking, functionalization, or phase transition processes were used to produce artificial tissues or soft artificial organs for substituting damaged artificial organs (especially blood vessels or artificial heart) or to improve the functions of living tissues [44,46,56,[58][59][60][61].…”

“…The supramolecular self-assembly offers the possibility to obtain a variety of biomaterials for improving everyday life with a minimum impact to environment. Thus, different polymeric architectures and morphologies were designed as drug carriers for controlled release and optimized targeting [6,41,58,59,62,63], wound healing materials [24,39,40], tissue engineering [4,5,[36][37][38]46,52,57], healthy food [19], or eco-friendly packaging [48,61]. In addition to the functional performances, the morphological stability and structural integrity of biomaterials determine their in vivo effectiveness [24][25][26][27][28][29]46,53,54].…”

“…If the crosslinking points are established by weak physical interactions, the water excess can determine the network disintegration up to complete dissolution. The amount of free and bound water can be determined by using different techniques and methods, such as: nuclear magnetic resonance, differential scanning calorimetry, X-ray powder diffraction, dielectric relaxation spectroscopy, quasi-elastic neutron scattering, infrared spectroscopy [93,94], diffusion or adsorption [40,41,59,62,63,95,96]. The main factors influencing the swelling process are: the crosslinking density, hydrophilicity of polymer chains, and characteristics of surrounding medium, such as pH or ionic strength and temperature.…”

Electrospinning of antibacterial and anti-inflammatory Ag@hesperidin core-shell nanoparticles into nanofibers used for promoting infected wound healing

“…The above mixture was prepared into electro spun nanofibers to form hydrogel (Ag-Hes@H). Hydrogels and nanofibrous materials are very attracting in medical application materials field [ 33–37 ]. Finally, the designed Ag-Hes@H was expected to have great potential for promoting infected wound healing in animal experiment.…”