Sustainable development of dual–templating molecularly imprinted polymers for biopurification

Abstract

The demand for bio–based products is increasing, but the development of efficient purification processes is lagging. However, typically these processes are expensive, non–specific and/or lack of efficiency. Molecularly imprinted polymers (MIPs) are synthetic affinity materials able to mimic the molecular recognition ability of natural molecules, offering a cost–effective alternative to replace the commercial affinity–driven materials based on proteins and antibodies. In this work, MIPs were developed using supercritical carbon dioxide (scCO2) technology using two approaches: i) one–templating (O–MIPs), using L–leucine (LEU) as template, and ii) a dual–templating (D–MIPs), using LEU and L–lysine (LYS) as templates, to evaluate their potential in the molecular recognition of amino acids in simple and complex aqueous solutions. MIPs produced in scCO2 have already shown good performances in organic and aqueous solutions, for small and non–polar template molecules. Herein, their applicability is extended to amino acids but also proteins. MIPs were produced using 2–vinylpyridine (VP) as functional monomer and ethylene glycol dimethacrylate (EGDMA) as crosslinker under scCO2 conditions. Polymers were obtained as white, ready–to–use dry powders. Their affinity performance was assessed by Static Binding Tests (SBTs) and Solid Phase Extraction (SPE) assays using different amino acids and proteins. The best SBT results was obtained by D–MIP with Qmax = 216 mg LEU + LYS/g D–MIP, and IFmax = 8.3. D–MIP also presented higher binding capacities to adsorb their templated–molecules by a dynamic process (SPE) (Qmax = 79 mg LEU + LYS/g D–MIP), and selectively bind their templates in a solution containing a protein (IFmax = 6.8). The green D–MIP provides a robust, tailor–made and sustainable alternative for biopurification processes.