Room temperature synthesis and binding studies of solution‐processable histamine‐imprinted microspheres

Abstract

Accurate quantification of histamine levels in food and in biological samples is important for monitoring the quality of food products and for the detection of pathophysiological conditions. In this study, solution processable histamine-imprinted microspheres were synthesized at 30°C via dilute free radical phototochemical polymerization technique using ethylene glycol dimethacrylate (EGDMA) as the crosslinker and methacrylic acid (MAA) as the monomer. The processability of the resulting polymer is dictated by the monomer feed concentration (eg, 4 wt% 80:20 EGDMA:MAA formulation) and solvent (acetonitrile). Whereas, the particle size is influ- These results demonstrated that histamine-selective imprinted polymers can be obtained readily using room temperature photochemical polymerization where these materials can be subsequently used as recognition element for optical-based histamine sensing. KEYWORDSfrontal analysis capillary electrophoresis, histamine, microspheres, photochemical polymerization, processable, thermal polymerization 1 | INTRODUCTION Solution-processable imprinted polymers are highly crosslinked submicron-sized polymeric particles (ie, microgels, nano-gels, microspheres, or simple nanoparticles) that form stable dispersions in a given solvent without changing their overall structure including their binding pockets. 1 These polymers also possess more accessible sites providing better binding kinetics. [2][3][4] Due to these unique properties, these imprinted polymers are ideal for catalysis, 3-6 for drug delivery or controlled release, 7 and for sensing. [8][9][10][11][12] These polymers have been prepared via solution polymerization, 3,4,12,13 conventional thermal and controlled radical precipitation polymerization, 1 and mini-emulsion and micro-emulsion polymerization, 14 where the resulting processable polymers can be easily characterized as macromolecules both as a solid or in solution form using standard techniques.Even with the numerous advantages, 1 major drawback in using these polymers is the nature of preparation where high dilution polymerization is required. In a typical molecular imprinting process, a target molecule acts as a template where functional and cross-linking monomers (pre-polymer) are initially allowed to organize and preassemble, and then copolymerized to form binding sites complementary to the target template. The polymer framework is held together by the highly cross-linked structure. 15 In a highly dilute condition, the formation of a stable pre-polymer complex is not favored. Instead, the condition shifts to favor the formation of free template and monomers, thereby affecting the stability of the complex. Gratifyingly, this problem may be circumvented by using template-monomer combination possessing excellent binding interactions or by shifting the equilibrium toward complex formation by running the polymerization reaction at lower temperature. 16,17

Studying molecular interactions via capillary electrophoresis and microscale thermophoresis: A review

“…It has been found a strong dependence of the binding parameters with the ionic strength and also that the concentration of polymeric adjuvant significantly modifies the ionic strength of the formulation, the extent of which can be estimated and corrected [58]. The applications of CE-FA [47,52,55,57,[145][146][147][148][149][150][151][152][153][155][156][157][158][159][160][161] and FACCE [58][59][60]154] are summarized in Table 3.…”