Method for purification of quantum dot-streptavidin conjugate

Abstract

The invention discloses a new method suitable for large-scale high-efficiency purification of a water soluble quantum dot-streptavidin conjugate, and belongs to the field of biotechnology. In allusion to the disadvantages that a conventional quantum dot-streptavidin conjugate has complex purification process and low recovery rate and difficultly realizes large-scale production, single-terminal aminated polyethylene glycol (HO-PEG-NH3) is adopted to seal residual carboxyl of the quantum dot-streptavidin conjugate, a surface zeta potential of the conjugate is reduced; by adjusting the pH value of a solution to 4.5, the net charge content of the conjugate in the solution is further reduced, and the large-scale high-efficiency purification of the quantum dot-streptavidin conjugate is achieved by an ordinary high-speed centrifugation method. The method simplifies experimental operation procedures of the quantum dot-streptavidin conjugate, reduces requirements on separation equipment, is suitable for large-batch purification of the quantum dot-streptavidin conjugate, allows the yield to be more than 85%, and allows fluorescence characteristics and biological activity of the conjugate to have no significant changes.

Description

technical field [0001] The invention relates to a new method for biological modification of nanometer materials and purification of conjugates, in particular to a new method for large-scale and efficient purification of quantum dot and streptavidin conjugates. Background technique [0002] Streptavidin is a protein with similar biological characteristics to avidin, which can highly specifically bind a water-soluble vitamin: D-biotin. It has a very strong affinity with biotin, and the relationship between them The Kd value is close to 10 -15 M. Complete streptavidin is a tetramer composed of four identical peptide chains, with a total molecular weight of about 66.5kDa, and each streptavidin molecule can tightly bind four biotin molecules, with an average of each peptide chain ( monomer) can bind a biotin molecule. The complete tetramer streptavidin also has good thermal stability and strong tolerance to strong acids, sodium dodecylsulfonate, urea, and guanidine hydrochlori...

AI Technical Summary

Problems solved by technology

In short, although the above purification methods can be used to obtain high-quality quantum dot streptavidin conjugates, there are still defects such as harsh operating conditions, complicated processes, and low yields, and it is difficult to achieve large-scale production.

Images