Gels: From Soft Matter to BioMatter

Progress in the investigation of soft-matter gels is discussed, and cutting-edge applications of BioMatter are demonstrated. Emphasis is placed on a series of high-performance hydrogels consisting of tetra-arm poly(ethylene glycol), called Tetra-PEG gels. Tetra-PEG gels are now well known for their extraordinarily uniform and monodisperse network structures, compared with those of conventional gels, and can be tuned depending on the given molecular weight, concentration, choice of pair prepolymers, hydrophilicity/hydrophobicity, thermosensitivity, composition, etc. The unique characteristics of Tetra-PEG gels are reviewed, and a variety of applications are demonstrated. Problems in their biomedical application are then raised, followed by a discussion of attempts to circumvent these issues.