Biodegradable Hydrogel Biomaterial Depots

Biomaterial depots were prepared using well characterized diblock copolypeptide hydrogels that are CNS biocompatible, biodegrade over several weeks in vivo and provide prolonged delivery of bioactive growth factors in CNS tissue for two or more weeks after injection18 (link),19 (link),37 (link),38 (link). Diblock copolypeptide hydrogel K₁₈₀L₂₀ was fabricated, conjugated with blue fluorescent dye (AMCA-X) and loaded with growth factor and antibody cargoes as described36 (link)–38 (link). Cargo molecules were as follows: Human recombinant FGF2, EGF and GDNF were purchased from PeproTech (Rocky Hill, NJ): (i) Human FGF2 (FGF-basic) (154 a.a.) Cat#100-18B-100UG, Lot#091608 C0617; (ii) Human EGF Cat#AF-100-15-100UG, Lot#0816AFC05 B2317; (iii) Human GDNF Cat#405-10-100UG, Lot#0606B64 A2517. Integrin-function-blocking Hamster anti-rat CD29 monoclonal antibody was purchased from BD Bioscience (San Diego, CA) as a custom order at 10.3mg/ml (product #624084; lot#7165896). Freeze dried K₁₈₀L₂₀ powder was reconstituted to 3.0% or 3.5% wt/vol in sterile PBS without cargo or with combinations of FGF2 (1.0µg/µl), EGF (1.0µg/µl), GDNF (1.0µg/µl) and anti-CD29 (5µg/µl). Diblock copolypeptide hydrogel formulations were prepared to have G′ (storage modulus at 10 rad s-1) between 75 and 100 Pascal (Pa), somewhat below that of mouse brain at 200 Pa37 (link),38 (link).