Fig. 5

Characteristic features of PLGA particles. PLGA particles were analyzed morphologically with SEM, evaluated for endotoxin contamination with the Limulus amebocyte lysate (LAL) test, and functionally assessed by their CCL25 release profile. Representative SEM images of the PLGA particles generated are shown in a i,ii with × 40 and 200 magnification at day one, iii, iv with × 40/ × 200 magnification after 14 days of degradation, v, vi with × 40/ × 200 magnification after 28 days of degradation and vii, viii with × 1000 magnification after 63 days of degradation. Scale bars represent 500 and 100 µm, respectively. b The results of the LAL test for the detection of endotoxins are shown for different stock solutions of CCL25 (10 and 500 nM) and the supernatant from PLGA particles (CL supernatant) compared to the test standards (0.1–10 nM). c The cumulative release in percent ± SD of CCL25 from PLGA particles over time until day 63 (n = 3) was determined by ELISA. CL CCL25-loaded, PLGA Poly (lactic-co-glycolic acid)