Optimized dyeing conditions of immunoprotein with reactive dye Procion Blue MX-7RX

For investigating the feasibility of using reactive dyes as an immunoassay marker, a dichlorine triazine dye, Procion Blue MX-7RX, was employed to stain the antibody against human serum albumin (anti-HSA). With the color intensity revealed in the immunochromatographic test strip as the objective variables, the optimal dyeing conditions were found as follows: pH 11.4, temperature 35.7 °C, molar ratio 188 (mol dye/mol antibody), and reaction time 45.6 min. The dyed-anti-HSA revealed a maximal color intensity of 8738 without apparent loss of antigen binding affinity.