## 1 Introduction  
The development of simple sensors able to detect and quantify specific analytes is a continually expanding sector. Among the several recognition elements that are necessary to build up a sensor, the molecularly imprinted polymers (MIPs) approach has received great attention in recent years toward obtaining sensing nanomaterials, since it is specific, cheap and stable to different conditions, albeit with lower sensitivity and selectivity in comparison to antibodies or other recognition elements [1]. Due to their enzyme and antibody mimicking approach, the \"lock and key\" mechanism, MIPs are usually defined as biosensors. Two different approaches can be used in preparing MIPs, the covalent and the non-covalent one. In the covalent approach, the imprinted molecule is covalently attached to the polymerizable molecule by using reversible covalent binding, and a chemical cleavage is necessary at the end of polymerization to remove the template. The most frequent approach is the non-covalent imprinting due to its simplicity and accessibility. In this approach, a specific binding site is built by self-assembly of the functional monomer, the chosen template and a cross-linker. The removal of the template in this case is by solvent extraction. MIPs can be used in several fields such as in extraction processes, as they are used as stationary phases for chromatography and SPE (solid phase extraction), in detection of small molecule analytes, in surface covering of gold and silver nanoparticles to use in Raman SERS (surface enhanced Raman scattering) or in drug delivery [2]. Regarding detection, these particular biosensors can be classified into electrochemical, optical or other sensors, depending on the transducer, and one of the main application fields is food safety. In fact, MIPs have been prepared for the detection of natural toxins, residues of pesticides, veterinary drugs, environmental contaminants from soil and water, abused additives and contaminants from processing and packaging [3]. To date, MIPs for sensing food analytes have often a relatively low sensitivity and suffer from matrix effect, but the fluorescence sensing technology has demonstrated to have the advantages of specific recognition and specific adsorption of molecular imprinting, together with a high sensitivity and a high selectivity. Fluorescent materials with both these characteristics are therefore important in the rapid detection of food quality [4]. Moreover, the design of an imprinted nanomaterial capable to activate a signal such as fluorescence emission, rather than quenching, would be very helpful to improve sensitivity. Fluorescent imprinted polymers usually have been obtained with naphtalimide fluorophores, quantum dots, and other sensing molecules as fluorescein. Very few MIPs containing fluorescein give an enhancement of emission of the fluorescent signal upon interaction with the target [5; 6; 7; 8]. To this end, in the present work, the non-covalent approach has been exploited to prepare several imprinted nanomaterials (nanogels), able to capture specifically tyrosol (TY) **1** and hydroxytrol (HT) **2** (Figure 1). The target molecules are important analytes in the quality evaluation of olive oil and of olive leaves extracts. They represent key compounds in the beneficial effect of the Mediterranean diet, which has a strong influence in preventing cardiovascular diseases, and consumption of olive oil is one of the factors contributing to the healthiness of this diet. Clinical studies proved that substituting saturated fatty acids with the monounsaturated ones present in olive oil, which is particularly rich with oleic acid, a decrease in LDL (low density lipoprotein) pragmatic concentration is observed. Recently, also the minor components of olive oil were studied in protecting the oxidative stress of the LDL, attributing to the phenols and polyphenols the antioxidant properties [9].