Fabrication of low-fouling, high-loading polymeric surfaces through pH-controlled RAFT

• Published in: RSC advances Vol. 1; no. 34; pp. 232 - 2312
• Main Authors: Jesmer, Alexander H, Huynh, Vincent, Wylie, Ryan G
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 27.05.2020; The Royal Society of Chemistry
• Subjects: Addition polymerization; Antibodies; Binding; Biotin; Chain transfer; Chains (polymeric); Chemistry; Complex media; Control surfaces; Fluorescein; Fouling; Immobilization; Light irradiation; Macrophages; Mushrooms; Polymers; Protein adsorption; Proteins; Reagents; Termination (polymerization); Transition metals
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/d0ra02693j

Low-fouling and high-loading surfaces are increasingly important for biosensing and blood purification technologies. Selective and efficient target binding from complex media can be achieved with poly(carboxybetaine) (pCB) surfaces that consist of a dense brush layer to resist non-specific protein adsorption and a sparse "mushroom" upper layer for high-density capture agent immobilization ( i.e. high-loading). We developed pH-controlled surface-reversible addition-fragmentation chain-transfer (S-RAFT) polymerization to simplify fabrication of multi-modal, low-fouling and high-loading pCB surfaces without the need for quenching or re-initiation steps, toxic transition metals or light irradiation. Multi-modal polymer layers were produced through partial polymer termination by temporarily raising the pH to aminolyse a fraction of dormant chain transfer agents (CTAs); remaining polymer chains with intact CTAs continued uninterrupted extension to create the "mushroom" upper layer. The multi-modal pCB surfaces were low-fouling towards proteins (<6.7 ng cm −2 ), and macrophages. Compared to mono-modal brush surfaces, multi-modal pCB surfaces were high-loading with 5-fold greater capture agent immobilization ( e.g. antibody) and 4-fold greater target binding ( e.g. biotin-fluorescein). pH-Controlled surface-reversible addition-fragmentation chain-transfer (S-RAFT) polymerization yields a one-pot synthesis for bimodal polymeric surfaces for improved capture agent immobilization.