Biomimetic Material Synthesis and its Application for Emerging Contaminant: Mini Review

Molecularly Imprinted Synthetic Polymers known as MIP (Molecularly Imprinted Polymers) accomplish specific recognition by forming special cavities to complementary in size as well as the shape to the analyte. Molecularly imprinted polymers are molecules that selectively combine with template molecules during manufacturing processes throughout a “lock-and-key” mechanism [1,2]. In short, we can say it is a procedure that generates templateshaped cavities in polymer matrices with a memory of template molecules. Molecular printing techniques were reported in 1972 when Wulff [3] and Takagish [4] published the preparation of organic polymers.

The molecular imprinting synthesis technique is based on the presence of the appropriate functional monomer, cross-linked agent around an analyte, radical initiator, and porogenic solvent. The functional monomer helps in the formation of the polymer, unit by unit. The selection of the most suitable type of monomer is based on the characteristics and functional chemical groups of the template, with which it must form a stable complex. Moreover, the interactions between the template and monomers are important for selective pores in the polymeric structure. The functional monomers are of different types either Covalent or noncovalent functional monomers and computer simulation helps in the selection of the best monomers. Cross-linking agent responsible for generating the three-dimensional structure of the polymer and for providing it with mechanical stability, rigidity and also protect the structure during the washing of template molecule. Selectivity also depends on the type as well as the amount of cross-linking agent used in the synthesis of MIP. In the polymerization of MIP, a template molecule (analyte) is printed in such a way that a polymeric cavity is formed. The target analyte (template) are pesticides, drugs, steroids, hormones, vitamins, metabolites or it may depend on interest. After formation, the polymer is washed to remove the remaining analyte, to obtain the selective cavity in the polymeric structure of MIP, which contains active sites complementary to the shape and size of the analyte of interest. After washing, the clean polymer will have uniformly sized nanocavities capable of selectively retaining the analyte in a complex sample [5,6].

The initiator is responsible for initiating the free radical polymerization process. There are different types of initiators are used depending on the method used during synthesis. While the porogenic solvent is also important to give the morphology, create pores of the selective cavity, and shows characteristics that compound involved in polymerization must be soluble and have low polarity to reduce the interference and selectivity. Similarly, for the comparison study, a Non-Imprinted Polymer (NIP) was synthesized as a control material. The NIP is synthesized without the presence of the template molecule and, therefore, there are no selective cavities [7]. The Schematic diagrams of the synthesis of MIP are presented in Figure 1. Similarly, Magnetic Molecularly Imprinted Polymer (MMIP) has demonstrated an alternative technique in environmental research for the deduction of organic pollutants from water because of its small size, high surface area, and selectivity toward target molecules [8,9]. The schematic diagram of the preparation of the core-shell method is given in Figure 2.

Figure 1:Schematic representation of the molecular imprinting process, source (author).

Figure 2: Schematic representation of the magnetic molecular imprinting process, source (author)

In recent years, research related to these polymers has increased significantly, as they have demonstrated great potential due to their selective recognition of diverse molecules and a wide variety of applications in different samples. MIPs are artificially engineered materials utilized as recognition components due to their higher thermal stability than biological recognition materials, reusability, and selectivity compared to biological recognition receptors. The MIP proficiently removes the organic and inorganic toxic compounds from the fluid phase. The tracing of important contaminations, preparation, and their detection in the real environmental samples via Molecular Imprinted Polymer (MIP) are present in Table 1.

Table 1: Application of MMIPs for selective extraction of analytes from real samples

This mini review shows that MIP was successfully utilized for the determination of antibiotics, heavy metals, personal care products, pesticides, dye, and emerging pollutants present in very small amounts in the water. Similarly, magnetic-MIP is also viewed as a kind of potential Sorbent for the determination of the various analyte. Magnetic molecularly imprinted polymer and magnetic non-imprinted polymer be synthesized for rapid and selective quantification of emerging contaminants in the real food as well as river water samples.

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