Bioink

A hydrogel precursor composition for bioink comprising:

• i. a first component comprising a hyaluronic acid (HA) component conjugated to
• a. plurality of carbohydrazide groups (—CONHNH2) wherein the carbohydrazide groups are conjugated to 5-20% of disaccharide repeat units of the HA component of the first component via linker L1 wherein said linker is —NHNH—, and
• b. plurality of catechol groups wherein the catechol group are conjugated to 1-20% of disaccharide repeat units of the HA component of the first component via a linker L2, wherein said linker is —NH(CH2)2—;
• ii. a second component comprising a hyaluronic acid (HA) component conjugated to plurality of aldehyde groups, wherein the aldehyde groups are conjugated to 5-50% of the disaccharide repeat units of the HA component of the second component via a linker L3, wherein said linker is —NHCH2 wherein molecular weight of the HA component of first component and the HA component of the second component is 100-300 kDa, and wherein the aldehyde groups are configured to form crosslinks with the carbohydrazide groups;
• and
• iii. a rheological modifier component;
• wherein the rheological modifier component comprises
• hyaluronic acid with a molecular weight of 1200 kDa-1900 kDa, and
• collagen with molecular weight of 250-300 kDa, and
• wherein the rheological modifier component comprises 2-50 wt-% from the total weight of the hydrogel precursor composition.