Recently,advanced engineering hydrogels that possess improved physicochemical performances have been fulfilled by design on the molecular scale and control over multiscale architecture.1 Self-healing hydrogels as promising candidates to spontaneously heal themselves upon mechanical damage and regain their original functionalities have been exploited on the basis of the concept of constitutional dynamic chemistry(CDC).2 To meet the progressive requirements of advanced engineering materials with superior physicochemical performances,self-healing and injectable hydrogels(AD hydrogels)based on agarose with pH-response were prepared through dynamic covalent Schiff-base linkages by simply mixing nontoxic agarose-—ethylenediamine conjugate(AGNH2)and dialdehyde-functionalized polyethylene glycol(DFPEG)solutions(Figure 1a).