To begin, add 100 microliters of prepared QD nanobeads to 200 microliters of phosphate buffer. Then add six microliters of EDC. After that, incubate the mixture for 30 minutes at room temperature on a rotary mixer.
Centrifuge the mixture at 13, 523 g for 10 minutes at room temperature and discard the supernatant. Next, add 100 microliters of phosphate buffer to the precipitate. Cover the tube with its lid and immerse it in the operational ultrasonic water bath until the precipitate is fully dispersed.
Disperse 100 micrograms of antibody in 200 microliters of phosphate buffer, and add the activated QD nanobead suspension to the antibody solution. Incubate the mixture at room temperature for 30 minutes with continuous rotation. Then remove excess antibodies by centrifugation at 6, 010 g for five minutes at room temperature, and carefully discard the supernatant.
To block the nanobeads, add 200 microliters of 1%casein solution to the residue. Cover the tube with its lid and immerse it into the operational ultrasonic water bath until the residue is fully dispersed. Incubate the mixture at room temperature for two hours with continuous rotation.
Add 100 microliters of preservative solution to the mixture and store at four degrees Celsius for subsequent use.
