Bioactive and chemically defined hydrogels with tunable stiffness guide cerebral organoid formation and modulate multi-omics plasticity in cerebral organoids

Organoids are an emerging technology with great potential in human disease modelling, drug devel-opment, diagnosis, tissue engineering, and regenerative medicine. Organoids as 3D-tissue culture sys-tems have gained special attention in the past decades due to their ability to faithfully recapitulate the complexity of organ-specific tissues. Despite considerable successes in culturing physiologically relevant organoids, their real-life applications are currently limited by challenges such as scarcity of an appropri-ate biomimetic matrix. Peptide amphiphiles (PAs) due to their well-defined chemistry, tunable bioactiv-ity, and extracellular matrix (ECM)-like nanofibrous architecture represent an attractive material scaffold for organoids development. Using cerebral organoids (COs) as exemplar, we demonstrate the possibility to create bio-instructive hydrogels with tunable stiffness ranging from 0.69 kPa to 2.24 kPa to culture and induce COs growth. We used orthogonal chemistry involving oxidative coupling and supramolec-ular interactions to create two-component hydrogels integrating the bio-instructive activity and ECM -like nanofibrous architecture of a laminin-mimetic PAs (IKVAV-PA) and tunable crosslinking density of hyaluronic acid functionalized with tyramine (HA-Try). Multi-omics technology including transcriptomics, proteomics, and metabolomics reveals the induction and growth of COs in soft HA-Tyr hydrogels contain-ing PA-IKVAV such that the COs display morphology and biomolecular signatures similar to those grown in Matrigel scaffolds. Our materials hold great promise as a safe synthetic ECM for COs induction and growth. Our approach represents a well-defined alternative to animal-derived matrices for the culture of COs and might expand the applicability of organoids in basic and clinical research. Statement of significance Synthetic bio-instructive materials which display tissue-specific functionality and nanoscale architecture of the native extracellular matrix are attractive matrices for organoids development. These synthetic ma-trices are chemically defined and animal-free compared to current gold standard matrices such as Ma-trigel. Here, we developed hydrogel matrices with tunable stiffness, which incorporate laminin-mimetic peptide amphiphiles to grow and expand cerebral organoids. Using multi-omics tools, the present study provides exciting data on the effects of neuro-inductive cues on the biomolecular profiles of brain organoids. (c) 2023 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.