Development, physico-chemical characterization and biological evaluation of silk fibroin/hyaluronic acid freeze-dried sponges for the trapping of Glioblastoma cells

Resumen

Glioblastoma (GBM) is a devastating tumour of the central nervous system. Despite an aggressive treatment, recurrence is inevitable, and the application of an effective therapeutic strategy remains a challenge. The breakthrough concept of cancer cell trap may offer new hopes and opportunities. The goal is to attract and confine the residual cancer cells surrounding the surgical cavity in a biomimetic polymeric scaffold delivering chemoattractive molecules. The stromal cell-derived factor-1α (SDF-1α), also called CXCL12, binds selectively to the CXCR4 receptor on the surface of infiltrative GBM cells and may be useful for inducing chemotaxis and the recruitment of residual GBM cells. In this work, series of freeze-dried sponges were prepared by combining silk fibroin (SF), hyaluronicacid (HA), poly-L-lysine (PLL) and heparin crosslinked with N-(3-dimethylaminopropyl)-N′-ethylcarbodiimidehydrochloride (EDC) and N-hydroxysulfosuccinimidesodium salt (NHS). Sponges showed high porosity (near 90%) with mean pore diameters ca. 60 μm and contained up to 95% water once hydrated. They presented a soft texture close to the one of a brain with a Young’s Modulus down to 6 kPa. Moreover, addition of SF in the formulation yielded sponges with greater stability in PBS than the HA-PLL sponges. SF-HA and SF-HA-hep sponges were able to retain 75% and 93% of the SDF-1 protein respectively after 7 days in PBS supplemented with enzymes (hyaluronidase and heparinase). In vivo studies showed that the SF-HA and SF-HA-hep sponges were well tolerated in rats’ brain and that the SF-HA-hep sponge did not release SDF-1α after 7 days in the brain.