Luminol enhancer solution

Particles were prepared as above, using DMEM (1 ml) containing 0.04–20 μg of xanthan gum. Particles were treated with EDTA, and the solution (20 μl) was transferred to polyvinylidene difluoride (PVDF) membranes using a dot blot apparatus (Bio-Rad). PVDF membranes were incubated into a blocking solution of phosphate buffered saline (PBS) containing 0.05% (v/v) Tween 20 and 3% (w/v) BSA at room temperature for 2 hrs, and probed with 15 ml of PBS containing 0.2 μg of biotinylated wheat germ agglutinin (WGA; Sigma) at room temperature for 1 hr. After two washing steps using 20 ml of blocking solution containing 1% (w/v) of BSA for 5 min, the PVDF membranes were incubated with 15 ml of blocking buffer containing streptavidin-horseradish peroxidase (HRP) antibody (ab7403, Abcam; 1:25,000) at room temperature with gentle agitation for 30 min. Membranes were washed four times with 20 ml of blocking solution. Signal was revealed with 1 ml of luminol enhancer solution (Promega) based on instructions provided by the manufacturer. Signal was revealed using X-ray radiographic films.