Surface functionalization of microscaffolds produced by high-resolution 3D printing: A new layer of freedom

This work introduces a scalable chemical modification strategy for microscaffolds (MS) fabricated by two-photon polymerization (2PP) to enable controlled biomolecule binding and release. The authors achieved aminolysis of PCL-based MS surfaces to create reactive primary amines, followed by heparin conjugation via EDC–NHS chemistry, enabling growth-factor loading (e.g., VEGF). Each MS exhibited tunable surface heparin content (8–40 ng) and VEGF release up to 55 ± 22 ng per 10 MS over 16 days. VEGF-loaded MS sustained endothelial tube formation in vitro for > 50 h, validating the platform for modular angiogenic tissue assembly. Mechanical testing confirmed that surface modifications did not affect scaffold stiffness (~220 ± 50 kPa). The study demonstrates a versatile microscale platform for bioactive factor delivery in tissue-engineering constructs.