Recent advances in chemical surface

Recent advances in chemical surface modification and polymeric biomaterials enable functionalization by grafting techniques to improve performance in biomedical applications at the interfaces of biomacromolecules, cells, tissues, and biomaterials. This review summarizes the common modification strategies, with a focus on biomedical applications. Among the three main grafting techniques, namely, grafting-to, graftingfrom, and grafting-through methods, the grafting-to method was developed first, but the grafting-from method has been the most common method to obtain high polymer densities or large layer thicknesses in the surface polymerization of biomaterials. Many methods of functionalization by surface modification of biomaterials for biomedical applications have been introduced in recent years, such as chemical grafting, plasmainduced graft polymerization, radiation-induced graft polymerization, ozone graft polymerization, and photoinduced graft polymerization.[184] Following the development of CRP, as reported in this review, the combination of CRP and the emerging, highly selective “click chemistry” and the application of this combination to existing surface grafting strategies are expected. In addition to the modification approaches, it is always necessary to realize green manufacturing, controllable processing, and low biotoxicity without extremely harsh experimental conditions during the modification process. Traditional solventbased grafting is known to often require specific procedures performed under harsh conditions, which might considerably impede its practical applications. According to new research, a facile solvent-free grafting-from method was reported to create ultralow biofouling and biocompatible surfaces, and this method was able to achieve better surface functionality than that of numerous traditional solvent-based grafting approaches.[185] This work could provide a new opportunity in exploring different angles of surface modification by considering the topic from the perspective of modification conditions. Although grafting strategies are promising tools and approaches to enhance the biomedical functions of surfaces such as antifouling properties or biocompatibility, additional studies are needed to determine the mechanisms and realize the full potential of these strategies. For example, future work could focus on achieving precise control of grafting onto different types of substrates with different shapes, elucidating the relationship between specific biomedical functions and the polymeric architectures grafted onto a surface, and achieving