One-step Conjugation Method for Antibodies with CdTe Quantum Dots Using Activated Dextran

The use of semiconductor quantum dots (QD) nanoparticles with emission spectrum in the visible region as a marker in immunoassays provides the user with an opportunity to detect the desired agent without using advanced equipment. Accordingly, the aim of this study was to present a one-step conjugation method for antibodies with CdTe quantum dots, using activated dextran. In this experimental study, CdTe nanoparticles were synthesized and the transmission electron microscope was used to study the morphology of the synthesized QD of CdTe and the size, concentration, and stability of the synthesized nanoparticles were evaluated. In order to stabilize the nanoparticles synthesized by BSA (Bovine Serum Albumin), they were coated and connected to antibodies with activated dextran. Immunosuppression tests were used to evaluate the conjugated antibodies. Findings: Spot and spherical nature were completely evident in the morphology of nanoparticles. The difference in QD and dBSA-QD displacement from the agarose gel confirmed the formation of dBSA-QD and the same dilution spectrum from nanoparticles was obtained in the presence and absence of BSA. Connecting with dBSA, in addition to maintaining and improving the properties of the nanoparticle's diffusion led to the creation of diverse functional groups for the next steps of nanoparticle connection. The fluorescence emission of nanoparticles was higher in both coated with dBSA and conjugated with antibodies than free nanoparticles. By using antibodies connected to nanoparticles, the detection limit of 30ng for protein antigen was obtained as an eye. In the conjugation process, in order to connect CdTe quantum dots to antibodies via dextran, by coating nanoparticles with a denatured BSA in addition to increasing the stability of nanoparticles, new functional groups are created on the surface of the nanoparticle.