Tunable Protein Adsorption by Zwitterionic Spherical Poly(CBAA)Brushes Prepared via Photoemulsion Polymerization

Zwitterionic polymer brushes are well-known as excellent hydrophilic and antifouling materials. However, theydemonstrate a certain degree of adsorption for proteins and other substances in practical application, and little research has beenconducted into this area. Herein, a facile and efficient approach was employed to prepare zwitterionic spherical polymer brushes,polystyrene-poly(2-carboxy-N,N-dimethyl-N-(3 '-acrylamidopropyl) ethanaminium inner salt) brushes (PS-PCBAA brushes).Specifically, the preparation process consists of three steps. First, polystyrene (PS) nanospheres were synthesized via conventionalemulsion polymerization, and then photoinitiator with terminal double bond was immobilized on the surface of the PS core bycopolymerizing with styrene (PS@HMEM). Finally, zwitterionic polymer chains (PCBAA) were grafted onto the surface of PS@HMEM via photoemulsion polymerization. The hydrodynamic diameter and size distribution, morphology, and chemicalcomposition of PS-PCBAA brushes were characterized. The interaction between PS-PCBAA brushes and proteins was investigatedby turbidity and size change. The interaction between brushes and proteins was mainly affected by two factors: the electrostaticinteraction between polymer chains and proteins, and the transition of zwitterionic polymers from a fouling polymer to a nonfoulingpolymer. This work provided a simple and environmentally friendly method for constructing zwitterionic materials that showedpotential application in the controllable adsorption and desorption of proteins.

Automated summary

Zwitterionic polymer brushes are widely used as hydrophilic and antifouling materials, but they still exhibit adsorption for proteins and other substances in practical application. In this study, a simple and efficient method was employed to prepare zwitterionic spherical polymer brushes and study their interaction with proteins. The findings have important implications for the development of zwitterionic materials with controllable adsorption and desorption of proteins.