## 1 Introduction  
Chemical and biochemical sensors are modern devices in analytical chemistry that simplify and miniaturize analytical determinations. Analytical methods based on modern sensor technology have solved many difficult analytical issues in research and society. Many scientific groups are working at the global level in the field and are reporting interesting results [1]. In general, conventional analytical methods have been extensively used due to their accuracy; nevertheless, most of these methods are expensive and require complex equipment, laboratory facilities, a high reagent consumption and well-trained personnel [2]. These drawbacks have prompted the research community to buildmore performant sensors for specific analysis of samples with complex matrices and very low concentrations, all at a lower reagent cost with inexpensive and easily-handled equipment, in order to perform in situ and on-site determinations [3]. Generally, a sensor is composed of three integrated parts (Figure 1), as follows: (i) a receptor for detecting the target analyte in a selective and sensitive manner, (ii) a physical transducer that converts the information obtained from the sensitive receptor into a measurable signal (usually an electric signal), and (iii) a suitable analytical device to process and show the significant signals formed by transducers and to calculate the results [4]. Biosensors are defined as analytical devices incorporating as a receptor biological material, such as enzymes, antibodies, nucleic acids, whole cells and tissues, a biologically derived material (i.e., engineered proteins, aptamers or recombinant antibodies) or a biomimetic material (i.e., molecularly imprinted polymers or combinatorial ligands). Depending on the incorporated sensitive material, the biosensors are classified as enzymatic, immune affinity recognition, DNA or whole-cell sensors; while considering the type of transducer, sensors can be classified as electrochemical, optical, acoustical, piezo-electrical, gravimetrical or thermal [1]. Each type of sensor class has other subclasses. For instance, the electrochemical sensors maybe amperometric (the majority), potentiometric, voltametric, etc. [5]. However, due to high production costs and the restricted operating conditions of these natural receptors, the development of artificial receptors with molecular recognition capacity, so-called synthetic receptors, have attracted a great interest as appropriate alternatives for the biological elements. Hence, among the existing techniques for the development of artificial receptors, high expectations are set out in the design of molecularly imprinted polymers (MIPs). MIPs are polymeric materials that are designed and produced with built-in molecular recognition properties. As a result of this fundamental attribute, a growing interest has been observed in their development as inexpensive and robust materials with sensitive and selective molecular recognition. Some of the top current applications that include the use of MIPs are associated with catalysis, separation sciences and monitoring/diagnostic devices for chemicals, biochemicals and pharmaceuticals [6,7]. MIPs have proven to possess important advantages as an alternative sensing material for biosensors, including the ease of preparation, storage stability, low cost, repeated uses without loss of activity, high mechanical strength and resistance to heat and pressure as well as to harsh chemical environments [8,9]. In a typical approach, the MI process (Figure 2) allows the creation of specific molecular recognition sites by the polymerization of a functional monomer in the presence of target molecules (called template) and of a high concentration of crosslinker. Following the template removal, by specific extraction procedures, the specific recognition cavities are revealed [10,11,12].This approach endows MIPs with tremendous specific binding properties, as they possess cavities with complementary size, shape and electronic environment with the target molecule [13].