- Controlled delivery of heparin-binding (HB) proteins represents a challenge in regenerative medicine strategies. Here, we describe the features of novel nanoparticles (NPs), spontaneously coassembled due to affinity interactions between HB proteins and the semisynthetic anionic polysaccharide, alginate-sulfate. The NPs efficiently encapsulated and protected the proteins from proteolysis. Injection of a combination of NPs encapsulating multiple therapeutic growth factors promoted effective and long-term tissue repair in animal models of severe ischemia (murine model of hindlimb ischemia and acute myocardial infarction in rats). This simple yet efficient NP fabrication method is amenable for clinical use.