Mechanisms of deformation and drug release of targeting polypeptides based on fibronectin induction

Polypeptide nano-carriers with deformation and sustained-release function have gained an attention in anti-tumor treatment. A multifunctional polypeptide with different motifs was discussed and the contribution of each motif to targeted drug release was analyzed by control studies. The transformation and drug release processes of polypeptides were investigated by molecular dynamics method to reveal their dynamics mechanism, and corresponding experiments were performed to verify the simulation results. We observed that the polypeptides could form NPs under the hydrophobic interaction between self-assembly motifs and the electrostatic repulsion between targeting motifs. Affected by the ligand-receptor interaction, the targeting motifs overcame the electrostatic repulsion to approach the ligand proteins, leading to the promotion of the binding of fibrous motifs and the transformation of NPs into NFs for better retention of drugs in the tumor tissues. In addition, the polypeptides with strong hydrophobicity exhibited excellent sustained-release efficiency. These insights allow drawing general conclusions contributed to the design of transformable polypeptide NPs: The decrease in the hydrophobicity of self-assembly motifs is beneficial for the enrichment of doxorubicin in tumor tissues, as well as the similar result can be obtained with the improvement of the hydrophobicity of fibrous motifs and the capability of target.