Aqueous solution of polymer having upper critical solution temperature, aqueous dispersion of particle modified with the polymer and method of storing the same

摘要

It is intended to provide an aqueous solution of a thermoresponsive polymer and an aqueous dispersion of a thermoresponsive particle, which show an upper critical solution temperature (UCST) and are capable of maintaining a dissolved state and a dispersed state, respectively, even if they are stored for a long period of time at a temperature at which a ligand such as an antibody or an antigen is not inactivated. A UCST lowering agent is incorporated in a predetermined amount in an aqueous solution of a thermoresponsive polymer which shows a UCST in a state of containing water or an aqueous dispersion of a thermoresponsive particle containing the polymer, thereby lowering the UCST of the aqueous solution or aqueous dispersion to less than the storage temperature, and the resulting aqueous solution or aqueous dispersion is stored.