In vivo transgene expression within fibrin hydrogels. Fibrin hydrogels containing either virus alone or HA/virus complexes were transplanted subcutaneously and expression profile was monitored for 28 days. (a) Represenative images of in vivo luciferase expression using bioluminescence imaging. (b) Quantification of luminescence as a function of time (n=6). Values at day 21 are statsitically different. Reprinted from J Control Rel, 157, Kidd ME, Shin S, Shea LD, Fibrin hydrogels for lentiviral gene delivery in vitro and in vivo, 80–85, 2012, with permission from Elsevier.