Hydrogel is a three-dimensional (3D) soft and highly hydrophilic, polymeric network that can swell in water and imbibe a high amount of water or biological fluids. Hydrogels have been used widely in various biomedical applications. Hydrogel may provide a fluidic tissue-like 3D microenvironment by maintaining the original network for tissue engineering. However, their low mechanical performances limit their broad applicability in various functional tissues. This property causes substantial challenges in designing and preparing strong hydrogel networks. Therefore, we report the triple-networked hybrid hydrogel network with enhanced mechanical properties by incorporating dual-crosslinking and nanofillers (e.g., montmorillonite (MMT), graphene nanoplatelets (GNPs)). In this study, we prepared hybrid hydrogels composed of polyacrylamide, poly (vinyl alcohol), sodium alginate, MMT, and MMT/GNPs through dynamic crosslinking. The freeze-dried hybrid hydrogels showed good 3D porous architecture. The results exhibited a magnificent porous structure, interconnected pore-network surface morphology, enhanced mechanical properties, and cellular activity of hybrid hydrogels.

The purpose of this review article is to outline the extended applications of polyurethane (PU)-based nanocomposites incorporated with conductive polymeric particles as well as to condense an outline on the chemistry and fabrication of polyurethanes (PUs). Additionally, we discuss related research trends of PU-based conducting materials for EMI shielding, sensors, coating, films, and foams, in particular those from the past 10 years. PU is generally an electrical insulator and behaves as a dielectric material. The electrical conductivity of PU is imparted by the addition of metal nanoparticles, and increases with the enhancing aspect ratio and ordering in structure, as happens in the case of conducting polymer fibrils or reduced graphene oxide (rGO). Nanocomposites with good electrical conductivity exhibit noticeable changes based on the remarkable electric properties of nanomaterials such as graphene, RGO, and multi-walled carbon nanotubes (MWCNTs). Recently, conducting polymers, including PANI, PPY, PTh, and their derivatives, have been popularly engaged as incorporated fillers into PU substrates. This review also discusses additional challenges and future-oriented perspectives combined with here-and-now practicableness.

Bacterial cellulose (BC) produced by Gluconoacetobacter hansenii is a suitable polymeric fiber network for wound-dressing purposes, but its lack of antibacterial properties limits it from healing bacterial wounds. We developed hydrogels by impregnating fungal-derived carboxymethyl chitosan to BC fiber networks using a simple solution immersion method. The CMCS–BC hydrogels were characterized using various characterization techniques such as XRD, FTIR, water contact angle measurements, TGA, and SEM to know the physiochemical properties. The results show that the impregnation of CMCS into BC fiber networks greatly influences BC’s improving hydrophilic nature, which is crucial for wound healing applications. Furthermore, the CMCS–BC hydrogels were studied for biocompatibility analysis with skin fibroblast cells. The results revealed that by increasing the CMCS content in the BC, biocompatibility, cell attachment, and spreading capacity also increase. The antibacterial activity of CMCS–BC hydrogels is shown using the CFU method against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). As a result, the CMCS–BC hydrogels exhibit more suitable antibacterial properties than those without BC due to the CMCS having amino groups that enhance antibacterial properties. Therefore, CMCS–BC hydrogels can be considered suitable for antibacterial wound dressing applications.