Delivery of chemotherapeutics using spheres made of bioengineered spider silks derived from MaSp1 and MaSp2 proteins.

Aim: Analysis of the properties and chemotherapeutics delivery potential of spheres made of bioengineered spider silks MS1 and MS2. Materials & methods: MS1 and MS2 derived from Nephila clavipes dragline silks - MaSp1 and MaSp2, respectively - formed spheres that were compared in terms of physicochemical properties, cytotoxicity and loading/release of chemotherapeutics. Results: MS2 spheres were more dispersed, smaller, of solid core, of higher beta-sheet structure content, and of opposite (negative) charge than MS1 spheres. Preloaded MS2 showed greater applicability for mitoxantrone, while postloaded for etoposide delivery compared with MS1 spheres. However, MS1 spheres were a better choice for doxorubicin delivery than MS2. Conclusion: Bioengineered silks can be tailored to develop a system with optimal drug loading and release properties. [ABSTRACT FROM AUTHOR]