Nature has developed materials that are integrated and effective at controlling their properties of adhesiveness and cohesiveness; the chemistry of these materials has been optimized during evolution. For example, a catechol moiety found in the adhesive proteins of marine mussels regulates its properties between adhesion and cohesion, rapidly adapting to environmental conditions. However, in synthetic materials chemistry, introduced chemical moieties are usually monofunctional, either being adhesive or cohesive; typically, this is not effective compared to natural materials. Herein, it is demonstrated that hyaluronic acid-catechol (HA-catechol) conjugates can exhibit either adhesiveness, functionalizing the surface of materials, or cohesiveness, building 3D hydrogels. Up to now, catechol-conjugated polymers have shown to be useful in one of these two functions. The usefulness of the polymer in stem cell engineering is demonstrated. A platform for neural stem cell culture may be prepared, utilizing the adhesive property of HA-catechol, and hydrogels are fabricated to encapsulate the neural stem cells, utilizing the cohesive property of the HA conjugate. Moreover, the HA-catechol hydrogels are highly neural stem cell compatible, showing better viability compared to existing methods based on HA hydrogels.