Photo-assisted generation of versatile zwitterionic carboxybetaine-based hypercrosslinked polymers for separation science

Abstract Zwitterionic super-hydrophilic polymeric monoliths showed fascinating attributes because of their excellent biocompatibility, hydrophilicity, and antifouling properties. However, their commercial developments are limited by their tedious preparation process and unsatisfactory performance. 1-Carboxy-N-methyl-N-di(2-methacryloyloxyethyl)methanaminium inner salt (CBMAX), an important zwitterionic functional monomer, which exhibits excellent hydrophilicity and extremely low protein adsorption from undiluted serum. However, no carboxybetaine based monolith has been reported to date. In this study, a rapid photo-assisted generation strategy based on a sole-monomer system (CBMAX being simultaneously used as monomer and crosslinker) was proposed for preparing versatile hyper-crosslinked zwitterionic carboxybetaine polymers in capillaries within only 5 min. It is significantly faster than the conventional sole-monomer (1 h) and multi-monomer system (over 12 h) via thermally-initiated polymerization approach. Moreover, a high column efficiency of 82000 plates/m, abundant electrostatic and hydrophilic interactions were achieved on the novel monolith due to the unique advantages of carboxybetaine. These excellent features were beneficial for the high-performance separation of various bioactive compounds (including nucleotide bases, phenols, benzoic acid and its derivatives, urea and allantoin) on this monolith. It is worth noting that this zwitterionic monolith exhibited good anti-protein adsorption ability as well as excellent enrichment capacity for N-glycopeptides from hIgG tryptic digest. In summary, the proposed photo-assisted generation strategy based on sole-monomer CBMAX is very successful and opens up a promising solution for the commercial development of zwitterionic super-hydrophilic polymeric monoliths.