Effect of 0.03% w/v Pluronic P123 on uptake of the YOYO-1 labeled gWIZLuc pDNA in NIH 3T3 and PC-3 cells. (A) Confocal microscopy images of live cells 2 h after NIH 3T3 cells transfection with PB25080-(A1, A2), P85PEI- (A3, A4) and Exgen 500- (A5, A6) based polyplexes without (A1, A3, A5) or with (A2, A4, A6) Pluronic P123. (B) Flow cytometry under the same transfection conditions as (A) comparing groups with/without Pluronic. (C) Flow cytometry of (C1) PC-3 cells alone and PC-3 cells transfected for 2h with (C2) naked pDNA, (C3) naked pDNA with Pluronic P123, (C4) PB25080/pDNA polyplex, and (C5) PB25080/pDNA polyplex with Pluronic P123. (B,C) Statistical comparisons between (B) untreated and Pluronic P123 treated groups or (C) pDNA alone and polyplex-treated groups were made as follows ** p < 0.01, n.s., not significant (n = 3).