Particles made of a novel recombinant spider silk protein rAcSp2 as delivery system for peptide drugs with anti-tumor activity

Abstract

The recombinant spider silk proteins (spidroins) are promising biomaterials for the use as drug delivery system (DDS) because of their non-cytotoxicity, low immunogenicity and customizable properties. However, most reported spidroin-based materials as DDS derive from the repetitive domain of dragline silk protein, limiting us to take advantage of their desirable properties for medical and industrial innovation. Here, we produced the recombinant aciniform silk protein (rAcSp2) that contains only the N-terminal domain and formulated it into nanoparticles for use as a DDS. We demonstrated that antitumor peptide drugs such as ChMAP-28 can be loaded onto rAcSp2 particles via electrostatic interaction, with a high loading capacity of up to 45 % (w/w) and nearly 100 % loading efficiency. In addition, the release of ChMAP-28 depends on the pH and ionic strength of the release buffer. In the meantime, rAcSp2 particles not only effectively reduce the toxicity of ChMAP-28 to normal cells, but also significantly enhance its anti-tumor activity. Therefore, our rAcSp2 particles are a promising novel particulate drug carrier system for the delivery of peptide drugs with anti-tumor activity.