Composite hydrogel for light-cured 3d cell-laden printing and preparation method and application thereof

A method for preparing a composite hydrogel, comprising:

• (1) grafting L-glutamic acid containing an amino group to a molecular chain of hyaluronic acid containing a carboxyl group through a peptide bond to obtain a hyaluronic acid-glutamic acid polymer (HA-Glu);
• dissolving the hyaluronic acid-glutamic acid polymer (HA-Glu), type I collagen (Col) and sodium chloride in an HCl solution to form a mixed solution of the hyaluronic acid-glutamic acid polymer and the collagen;
• (2) dissolving a photoinitiator lithium phenyl-2,4,6-trimethylbenzoylpho-sphinate (LAP) in an NaCl solution and heating a resulting solution in a water bath to form an LAP solution;
• (3) dissolving gelatin methacryloyl (GelMA) in the LAP solution, and heating a resulting solution in a water bath until the gelatin methacryloyl fully dissolves to form a gelatin methacryloyl solution;
• (4) dissolving sodium carboxymethyl cellulose (NaCMC) in the LAP solution, and heating a resulting solution in a water bath until the sodium carboxymethyl cellulose fully dissolves to form a sodium carboxymethyl cellulose solution;
• and
• (5) mixing the HA-Glu/Col mixed solution prepared in step (1), the GelMA solution prepared in step (3) and the NaCMC solution prepared in step (4), respectively, then adding a tartrazine with light-blocking property, and performing sterile filtration with a 0.22 μm sterile filter to finally obtain the composite hydrogel.