Nature: enzyme induced mineralized hydrogel is comparable to cartilage skin.

The animal's cartilage and skin are made up of more than 50% water and have a modulus of elasticity of up to 100 MPa, are tough and not easy to break (breaking energy of up to 9000 joules / m2) These characteristics make these biomaterials physically superior to existing synthetic hydrogels Recently, much progress has been made in the synthesis of tough and tough hydrogels Double web hydrogels have achieved skin like toughness, and inorganic organic composites show better performance However, these materials have high tensile properties due to their toughness In terms of stiffness, synthetic hydrogels can not compete with their natural counterparts The best example is only 10 MPa or even smaller elastic modulus Rauner et al have described the enzyme induced precipitation and crystallization of hydrogel containing calcium carbonate, but the material obtained is brittle This time they reported that the enzyme induced formation of amorphous calcium phosphate nanostructures was distributed evenly in polymer hydrogels Nicolas Rauner and so on will be embedded with alkaline phosphatase polymer hydrogel, in CaGP (glyceralphosphate) buffer solution species, adding 0.2mol L-1 triethanolamine, pH will be adjusted to 9.8, at room temperature, mineralization The mineralized gel achieves 1300 Joule breaking energy per square meter, which is better than most known water swelling synthetic materials They can also adjust their stiffness to 440 MPa, far more than cartilage and skin Photo courier: Figure 1 enzyme induced different polymer gel mineralization a) PDMA-l-TEG network calcification process Three kinds of films with different polymer networks (phea-l-teg, pdma-l-teg and paam-l-mbam) were prepared Alkaline phosphatase was introduced by photopolymerization Then add calcium 2-glycerophosphate (CAGP) calcification solution With the increase of time, the enzyme catalyzes the dephosphorylation of CAGP, leaving calcium and phosphate in the polymer network, showing an amorphous structure (white circle in the figure) These films changed from transparent to milky white, indicating mineralization; b) the stress-strain curves of phea-l-teg, pdma-l-teg and paam-l-mbam networks; c) the maximum Young's modulus (blue) and fracture energy (red) of the three networks These experiments have at least three parallel samples, all data are average, and the error line represents the standard deviation d) The SEM images of pdma-l-teg network calcification after 7 days; E) the SEM images of paam-l-mbam network calcification after 7 days The distribution of Figure 2 enzyme and inorganic substance in the hydrogel contains 0.4wt% fixed alkaline phosphatase silver plating hydrogel before mineralization (a) PHEA-l-TEG; b) PDMA-l-TEG; c) PAAm-l-MBAm; d) the young's modulus (black line) and swelling degree (grey dotted line) value of PAAm-l-MBAm mineralization after 3 days; E) scanning electron microscope photograph of 7 days after mineralization; f) SEM photos of 3 days after mineralization of paam-l-mbam The mechanical properties of Figure 3 hydrogel a) the young's modulus (histogram) of PAAm-l-MBAm calcified at room temperature and the fracture stress of notched specimen (Hong Xian); b) The fracture energy (histogram) of the corresponding paam-l-mbam composite, in which the content of inorganic components (calcium phosphate, cap) is marked in the column, the dry state (above) is expressed by mass fraction, the swelling state (below) is expressed by volume fraction; c) the young's modulus of the pdma-l-teg composite containing edpoa after mineralization for 7 days; d) The fracture energy (red) and Young's modulus (blue) of pdma-l-teg composite containing edpoa The calcification time: 4 days for 0wt% and 7wt% edpoa, 3 days for 1wt%, 2wt% and 5wt% edpoa, and 7 days for 10wt% edpoa There are at least three parallel samples in these experiments All the data are average values, and the error line represents the standard deviation The swelling PDMA-l-TEG network of Figure 4 transparent super hard composite hydrogel at room temperature for 7 days containing a) 1wt%; b) 2wt%; c) 10wt%EDPOA; the following correspond to respective scanning electron microscopy (large picture) and selected area electron diffraction photograph (small map); PDMA-l-TEG network containing 10wt%EDPOA in D) water; 10wt%EDPOA) swelling in calcified solution for 7 days; f) The swelling pdma-l-teg with 2wt% edpoa can carry 100g after 7 days of calcification.