Figure 1.

(A) Antiproliferative activity of MTX and HES-MTX against MC38 cells after a 72-h treatment was measured by MTT assay and the IC₅₀ value was calculated. (B) Representative histogram showing the interaction of FITC-conjugated HES-MTX and HES with MC38 cells and DCs after a 24-h treatment measured by flow cytometry. The numbers presented on the histograms represent mean fluorescence intensity (MFI) values. (C) Relative expression of folate receptor α (FRα) measured by real-time PCR in murine DCs and MC38 cells. (D) Representative sensorgrams from SPR measurements showing the association and dissociation phase of HES and HES-MTX conjugate from FBP immobilized on the surface of the CM5 chip. Sensorgrams are shown after subtraction for reference channel and blank measurements. Concentrations for both HES and HES-MTX are shown as anhydroglucose unit (AGU). (E) Size distributions are shown according to intensity measured by dynamic light scattering technique. d_H, mean hydrodynamic diameter. (F) Zeta (ζ) potential of HES-MTX as a function of pH measured by dynamic light scattering technique. The points denote experimental values determined for ionic strength 0.15 mM; IEP, isoelectric point. Results (A and C) are expressed as the mean ± SD calculated for at least three independent experiments. Differences between the groups were estimated by (A) Mann-Whitney test (*P<0.05) and (C) unpaired t-test (*P<0.05). HES, hydroxyethyl starch; MTX, methotrexate; DC, dendritic cells.