Temperature‐responsive “tadpole‐shaped” protein–polymer hybrids and their self‐assembly behavior

The temperature‐responsive poly (N, N‐diethylacrylamide) (pDEAAm) with narrower molecular weight distribution was prepared by the atom transfer radical polymerization and characterized by ¹HNMR and gel permeation chromatography. The temperature‐responsive “tadpole‐shaped” BSA–pDEAAm hybrids were fabricated via a free Cys‐34 residue of bovine serum albumin (BSA) site specifically binding to the end group disulfide bonds of pDEAAm and characterized by native‐polyacrylamide gel electrophoresis (Native‐PAGE) and matrix‐assisted laser desorption/ionization time of flight mass spectrometry. Their temperature‐responsive behaviors were measured by ultraviolet‐visible spectra (UV‐Vis). The lower critical solution temperature (LCST) of the pDEAAm was identified as 28°C, and the LCST of BSA–pDEAAm hybrids was identified as 31°C. The morphologies of BSA–pDEAAm hybrids self‐assembled in the aqueous solutions with two different temperatures at 25 °C and 40°C were investigated by transmission electron microscopy. Below the LCST of BSA–pDEAAm hybrids, the separate spherical nanoparticles were observed. In contrast, bundles and clusters were observed above the LCST of BSA–pDEAAm hybrids. The results suggested that the self‐assembly morphology of BSA–pDEAAm hybrids depended upon the pDEAAm block in BSA–pDEAAm hybrids, and the morphology transitions were effected by the LCST of BSA–pDEAAm hybrids. It would be expected to be used in biomedicine and materials science. Copyright © 2016 John Wiley & Sons, Ltd.