Fig. 3.

Retention of lentivirus on PS-PLG microspheres (A) Multiple doses of lentivirus encoding luciferase were incubated with 1 mg of PLG, PC-PLG, or PS-PLG microspheres for 30 min and centrifuged to remove the unbound viruses. After wash with PBS, the microspheres were mixed with 293 cells and seeded on the plate. Luciferase activity was measured at 2 days after seeding. Viruses without mixing with microspheres were used as control. (B) 2×10⁷ of LV-luc were mixed with microspheres and incubated at room temperature. At each time point, HEK-293 cells were mixed with the microspheres, which were not washed, and seeded to measure the luciferase activity after 2 days.