# Green Strategies for Molecularly Imprinted Polymer Development
## Green Strategies in MIP Development
### Microwave-Assisted MIP Synthesis  
Microwave has emerged as an alternative in MIP synthesis, dramatically decreasing the time required in the polymerization process, typically less than 1/10 of the required conventional heating. [93]. Although the mechanism is still not well understood and remains a point of debate [94], the benefits of this clean technology are very clear, promoting homogeneous and rapid heat transfer through the reaction mixture, leading to higher reaction rates, short-term polymerization processes, and high yields [95]. Microwave-assisted MIP preparation is a fast and simple methodology to obtain crosslinked polymers with controlled morphology and good recognition properties [96]. MIP-based devices have recently been explored using this promising technology, which provides a clean and less time-consuming approach to produce powders, layers, membranes, or hollow fibers. In 2009, [PERSON] et al. [93] reported the production of atrazine (ATR)-imprinted polymer layered magnetic particles by suspension polymerization using microwave heating, for tracing triazines on complex samples. MIP layered-magnetic particles were produced using MAA as monomer, TRIM and DVB as crosslinkers, AIBN as initiator, and water as a solvent media, using microwave heating for 120 min at 70 \({}^{\circ}\)C by increasing the temperature from room temperature in 3 min. Magnetic MIPs were obtained with uniform morphology and a narrow size distribution with an average particle size diameter ranging 100-200 \(\upmu\)m. The results obtained were comparable to the magnetic MIP prepared by conventional heating. MIP particles showed to have superior binding ability and selectivity for triazines, exhibiting higher imprinted factors compared with traditional ones. The process had a dramatic reduction in the time of the polymerization reactions. When a dual-phase solvent system of _n_-hexane and water was used in the same polymerization system, the imprinting efficiency of ATR increased from 0.5 to 4.4, and the sensitivity for seven triazines (presented in tomato, strawberry juice, and milk) increased 3.1-6.6 times compared with pure aqueous medium. The results opened up the possibility for further use of MIP in other aqueous media, such as biological fluids [97]. Microwave induced caffeine-imprinted polymer polymerization was described by [PERSON] et al. [98]. MAA, EGDMA, and AIBN were used as monomer, crosslinker, and initiator, respectively. Polymerization reactions were carried out in a microwave reactor, and heated at 150 W for 14 min at 60 \({}^{\circ}\)C. Agglomerates of nanoparticles were obtained, which were further packed on SPE columns, and the binding affinity and selectivity were evaluated with caffeine and THO. This microwave-assisted process reduced the preparation time by 70-fold when compared with conventional methods. In another example, also reported by [PERSON] et al. [96], indole-3-acetic acid (IAA)-MIP layered magnetic beads were developed through suspension polymerization under microwave heating, for application in the isolation and enrichment of auxins from plant tissues. 4-Vpy and silylated \(\beta\)-cyclodextrintrim (\(\beta\)-CD) were used as monomers alone or as co-monomers, TRIM as crosslinker, and AIBN as initiator. IAA-MIP magnetic beads were obtained as homogeneous spherical shape particles with a medium diameter between 50 to 200 \(\upmu\)m. The MIP layer was porous and presented a rough surface with high surface area. MIP-magnetic particles revealed higher binding capacity for IAA when both monomers (4-VP and silylated \(\beta\)-CD) were used. Kaempfer-MIP microspheres were also prepared by microwave-assisted polymerization, for the detection of kaempfer content in traditional Chinese medicines [99].