The DNA-immobilized membranes weighing 3.5 mg each were
first incubated with 1 mL of 1.5 mg/mL bovine serum albumin,
shaken at 300 rpm for 6 h at room temperature in an Eppendorf tube
(Protein LoBind) in order to reduce the non-specific binding. After
incubation, the membranes were repeatedly washed with distilled
water (each sample: 2 mL × 5 for 10 × 5 min) to remove the traces of
unbound albumin. Each membrane was then incubated with 0.5 mL
of 10 g/mL antibody solution for 3 h in an ice bath (around 4 ◦C)
on a mechanical shaker (500 rpm) in an Eppendorf tube (Protein
LoBind). After incubation, the membranes were removed, and theremaining antibody solution was used to determine the amount of
IgG bound by membranes using the mouse anti-dsDNA IgG ELISA
Kit. In addition, 2, 1, 0.5, 0.25 g/mL IgG solutions were also prepared for the standard curve for ELISA.