Fig. 3.

Rhodamine intracellular accumulation and extracellular release from MSCs. (A) To quantify the intracellular accumulation of rhodamine over time, MSCs loaded with 0.1 mg/mL or 0.5 mg/mL of rhodamine-PLGA particles were permeabilized with 5 mg/mL of L-lysine at 4 hr, 2 days, 4 days, 7 days, or 10 days, the permeabilized cells were discarded, and the dye concentration in the lysate was assessed with UV-Spectrophotometry. (B) Kinetics of rhodamine dye released into the culture media from MSCs modified particles versus a suspension of PLGA particles without cells. 200 μl of a 0.1mg/mL rhodamine-PLGA particle solution was added to the MSCs leading to internalization of ~19 μg and release was examined in 500 μl of media. To examine release of dye from particles without cells, conditions were normalized to the experimental group with ~19 μg of particles suspended in 500 μl of PBS.