## 4 Molecular Imprinting Using MIP Particles Embedded in Pastes or Inks
The electrochemical MIPs were incorporated in a composite paste SPE for the detection of an organic pollutant, Bisphenol A (BPA). The results proved the reliability of the device with an LOD as low as 0.06 nM and also the selectivity vs. carbamazepine and ketoprofen. BPA was also detected using a simple and ultra-low-cost, disposable paper-based potentiometric sensor, reported by [PERSON] et al. [120]. The prepared BPA-MIP nanobeads were mixed with the PVC membrane cocktail and incorporated by dropcasting into recyclable and biodegradable paper. The sensor was proven to be selective towards other phenols, exhibiting a detection limit of 0.15 \(\upmu\)M.  
An entrapment agent such as poly(methyl methacrylate) (PMMA) was suitable to carry out the incorporation of the synthetized MIP particles. For example, a QCM-based sensor for volatile organic compounds was prepared by spin coating a dispersion containing the MIP particles and PMMA on an AT quartz crystal resonator. The resulting devices tested towards toluene or p-xylene vapor showed potential for developing QCM sensors with MIP [121]. An interesting design of a biosensor for detecting lipopolysaccharideaccharides (LPS) derived from _Pseudomonas aeruginosa_ was proposed by [PERSON] et al. [122] using MIP-modified SPCE. As described in their research, the strategy was based on doping the mixture with electroactive particles of zinc oxide, while the sol-gel precursor solution was dripped directly onto the SPCE using the dropcasting method. The MIP films prove stability at re-use, recognizing the LPS from _Pseudomonas aeruginosa_ to a greater extent than the LPS from _Escherichia coli_, when using 16.7 \(\upmu\)g/mL aqueous LPS solutions. Another successful attempt, accomplished by [PERSON] et al. [30], for preparing electrodes modified with MIP layers, refers to imprinting rifamycin SV (RSV), a macro-cyclic antibiotic. Their study involved the drop coating of the electrode surface with a solution of a preformed polymer (polyphosphazenes) as recognition element. The final electrode exhibited selectivity towards dopamine and NADH as well as excellent reusability up to 25 times without signs of film loss or memory effects. The same group investigated the behavior of diclofenac by modifying carbon composite electrodes of different nature (polytetrafluoroethylene-graphite, epoxy graphite and epoxy-carbon black) with MIP particles. The drop coating method was also used for the modification of hanging a mercury drop electrode (HMDE) with MIP-DMF casting solution, which was applied in the determination of ascorbic acid [123]. One interesting approach used in the preparation of electrodes modified with MIP, is based on spin coating. The study carried out by [PERSON] and co-workers [124] targeted the preparation of a sensor for phenylephrine detection. In this respect, precursor solution for MIP, prepared in the presence of phenylephrine (as template), was dropped onto the surface of a GCE and the excess solution was eliminated by spin coating. The modified electrode was used in the determination of phenylephrine. Some years later, [PERSON] et al. [125] developed a biomimetic piezoelectric quartz crystal sensor for the determination of antibiotic chloramphenicol in food products. In their work, an MIP sensing layer was obtained by spin coating using a home-made device. The performance of this sensor refers to a sensitivity of about 73 Hz/log (conc., \(\upmu\)g-mL\({}^{-1}\)), a detection limit of 7 \(\times\) 10\({}^{-8}\)\(\upmu\)g-mL\({}^{-1}\) and good repeatability (rsd below 10%). The development of an electrochemical sensor for 1-hydroxyyrene (1-OHP) based on a molecular imprinted TiO\({}_{2}\) gel matrix was also described by the group of [PERSON] [126]. The 1-OHP-imprinted films were prepared by spincoating using film-forming stock solutions on quartz plates.