Hydrogel-integrated graphene superstructures for tissue engineering: From periodontal to neural regeneration

Hydrogels, due to their excellent biochemical and mechnical property, have shown attractive advantages in the field of wound dressings. However, a comprehensive review of the functional hydrogel as a wound dressing is still lacking. This work first summarizes the skin wound healing process and relates evaluation parameters and then reviews the advanced functions of hydrogel dressings such as antimicrobial property, adhesion and hemostasis, anti-inflammatory and anti-oxidation, substance delivery, self-healing, stimulus response, conductivity, and the recently emerged wound monitoring feature, and the strategies adopted to achieve these functions are all classified and discussed. Furthermore, applications of hydrogel wound dressing for the treatment of different types of wounds such as incisional wound and the excisional wound are summarized. Chronic wounds are also mentioned, and the focus of attention on infected wounds, burn wounds, and diabetic wounds is discussed. Finally, the future directions of hydrogel wound dressings for wound healing are further proposed.

Isolated graphene, a nanometer-thick two-dimensional analog of fullerenes and carbon nanotubes, has recently sparked great excitement in the scientific community given its excellent mechanical and electronic properties. Particularly attractive is the availability of bulk quantities of graphene as both colloidal dispersions and powders, which enables the facile fabrication of many carbon-based materials. The fact that such large amounts of graphene are most easily produced via the reduction of graphene oxide--oxygenated graphene sheets covered with epoxy, hydroxyl, and carboxyl groups--offers tremendous opportunities for access to functionalized graphene-based materials. Both graphene oxide and graphene can be processed into a wide variety of novel materials with distinctly different morphological features, where the carbonaceous nanosheets can serve as either the sole component, as in papers and thin films, or as fillers in polymer and/or inorganic nanocomposites. This Review summarizes techniques for preparing such advanced materials via stable graphene oxide, highly reduced graphene oxide, and graphene dispersions in aqueous and organic media. The excellent mechanical and electronic properties of the resulting materials are highlighted with a forward outlook on their applications.

Graphene and its chemical derivatives have been a pivotal new class of nanomaterials and a model system for quantum behavior. The material's excellent electrical conductivity, biocompatibility, surface area and thermal properties are of much interest to the scientific community. Two-dimensional graphene materials have been widely used in various biomedical research areas such as bioelectronics, imaging, drug delivery, and tissue engineering. In this review, we will highlight the recent applications of graphene-based materials in tissue engineering and regenerative medicine. In particular, we will discuss the application of graphene-based materials in cardiac, neural, bone, cartilage, skeletal muscle, and skin/adipose tissue engineering. We will also discuss the potential risk factors of graphene-based materials in tissue engineering. In conclusion, we will outline the opportunities in the usage of graphene-based materials for clinical applications.