Affinity-triggered hydrogels were created using one of the most selective and high-affinity pairs found in Nature, avidin-biotin. The multimerization of biotin was studied by conjugation into different multi-arm polyethylene glycol molecules. Depending on the multimerization, assemblies with tunable affinity constant were obtained leading to hydrogels with different mechanical properties and controllable erosion time and profiles. The results showed that mimicking natural multivalency gave rise to robust biocompatible hydrogel with applications in tissue engineering and stem cell research. The study results from ongoing collaboration between Cecília Roque (FCT-NOVA) and Tiago Fernandes (DBE-Técnico) and was recently published in the ACS journal Biomacromolecules.