PDS polymers preferentially bind C1498 cells and debris ex vivo, correlating with thioredoxin expression. (A-C) CD45.1 mice were inoculated with 1 million C1498 cells IV (n = 4). After 2 days, blood was collected, and white blood cells were isolated and incubated with labeled p(PDS-Man). Shown are (A) relative polymer binding to dead vs live cells or to (B) C1498 cells vs other CD45⁺ immune cells, as well as (C) overall intracellular Trx-1 levels in C1498 cells vs other CD45⁺ immune cells. (D-E) Separately, C57Bl/6 mice were inoculated with 1 million C1498 cells intravenously (n = 4-5). After 3 days, a subset of mice was treated intraperitoneally with cytarabine, and after 4 hours, blood was collected. Whole blood was incubated with labeled p(PDS-Man). Red blood cells were removed via ACK lysis, and remaining cells were stained for flow cytometry. (D) Intracellular Trx-1 levels were quantified separately in cells that were polymer⁺ and polymer^–. (E) Frequency of polymer⁺ cells is correlated with Trx-1 expression. All data are plotted as mean ± SEM (n = 3). Statistical analyses were performed using unpaired t tests (A-C), ordinary 2-way analysis of variance with multiple comparisons (D), and Pearson correlation. ∗P < .05; ∗∗P < .01; ∗∗∗∗P < .0001.