title: Well-defined hydrophilic molecularly imprinted polymer microspheres for efficient molecular recognition in real biological samples by facile RAFT coupling chemistry.
abstract: A facile and highly efficient new approach (namely RAFT coupling chemistry) to obtain well-defined hydrophilic molecularly imprinted polymer (MIP) microspheres with excellent specific recognition ability toward small organic analytes in the real, undiluted biological samples is described. It involves the first synthesis of "living" MIP microspheres with surface-bound vinyl and dithioester groups via RAFT precipitation polymerization (RAFTPP) and their subsequent grafting of hydrophilic polymer brushes by the simple coupling reaction of hydrophilic macro-RAFT agents (i.e., hydrophilic polymers with a dithioester end group) with vinyl groups on the "living" MIP particles in the presence of a free radical initiator. The successful grafting of hydrophilic polymer brushes onto the obtained MIP particles was confirmed by SEM, FT-IR, static contact angle and water dispersion studies, elemental analyses, and template binding experiments. Well-defined MIP particles with densely grafted hydrophilic polymer brushes (∼1.8 chains/nm(2)) of desired chemical structures and molecular weights were readily obtained, which showed significantly improved surface hydrophilicity and could thus function properly in real biological media. The origin of the high grafting densities of the polymer brushes was clarified and the general applicability of the strategy was demonstrated. In particular, the well-defined characteristics of the resulting hydrophilic MIP particles allowed the first systematic study on the effects of various structural parameters of the grafted hydrophilic polymer brushes on their water-compatibility, which is of great importance for rationally designing more advanced real biological sample-compatible MIPs.
authors.affiliation: Key Laboratory of Functional Polymer Materials, Ministry of Education, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), and College of Chemistry, Nankai University , Tianjin 300071, P. R. China.
authors.forename: Man
authors.initials: M
authors.lastname: Zhao
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Chen
authors.forename: Hongtao
authors.initials: H
authors.lastname: Zhang
authors.forename: Husheng
authors.initials: H
authors.lastname: Yan
authors.forename: Huiqi
authors.initials: H
authors.lastname: Zhang
mesh_terms: D057927:Hydrophobic and Hydrophilic Interactions; D008863:Microspheres; D054802:Molecular Imprinting; D015394:Molecular Structure; D010316:Particle Size; D058105:Polymerization; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D011108:Polymers