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Molecular imprinting is the process of template-induced formation of specific recognition sites in a polymer. Synthetic receptors prepared using molecular imprinting possess a unique combination of properties such as robustness, high affinity, specificity, and low-cost production, which makes them attractive alternatives to natural receptors. Improvements in polymer science and nanotechnology have contributed to enhanced performance of molecularly imprinted polymer (MIP) sensors. Encouragingly, recent years have seen an increase in high-quality publications describing MIP sensors for the determination of biomolecules, drugs of abuse, and explosives, driving toward applications of this technology in medical and forensic diagnostics. This review aims to provide a focused overview of the latest achievements made in MIP-based sensor technology, with emphasis on research toward real-life applications. Highlights Electrochemical and optical sensing based on molecularly imprinted polymers (MIPs) has particular relevance in real-life applications and point-of-care testing in real human samples. MIPs are a leading technology for sensing molecules where there is no available bioreceptor. MIP nanoparticles can be used for direct and indirect detection (labeled or label free). The sensitivity of MIP-based sensors can be enhanced by coupling with nanomaterials such as graphene oxide, carbon nanotubes, or nanoparticles. The present challenges and perspectives of MIP-based electrochemical and optical sensors include exploring the market niches for MIP sensors and identifying the necessary steps toward commercialization. [ABSTRACT FROM AUTHOR]

• Electroactive molecularly imprinted polymer nanoparticles (nanoMIPs) are robust actuators due to their polymeric nature. • Graphene-assisted nanoMIPs-based sensors are easily integrated and compatible with the mass production of sensor devices. • Sensors were evaluated on spiked human plasma and street samples,also validated successfully using UPLC-MS. • NanoMIP-based sensors can be applied in clinical and forensic analysis. Screening drugs on the street and biological samples pose a challenge to law enforcement agencies due to existing detection methods and instrument limitations. Herein we present a graphene-assisted molecularly imprinted polymer nanoparticle-based sensor for amphetamine. These nanoparticles are electroactive by incorporating ferrocene in their structure. These particles act as specific actuators in electrochemical sensors, and the presence of a ferrocene redox probe embedded in the structure allows the detection of non-electroactive amphetamine. In a control approach, nanoparticles were covalently immobilised onto electrochemical sensors by drop-casting using silanes. Alternatively, nanoparticles were immobilised employing 3D printing and a graphene ink composite. The electrochemical performance of both approaches was evaluated. As a result, 3D printed nanoMIPs/graphene sensors displayed the highest selectivity in spiked human plasma, with sensitivity at 73 nA nM−1, LOD of 68 nM (RSD 2.4%) when compared to the silane drop cast electrodes. The main advantage of the optimised 3D printing technology is that it allows quantitative determination of amphetamine, a non-electroactive drug, challenging to detect with conventional electrochemical sensors. In addition, the cost-efficient 3D printing method makes these sensors easy to manufacture, leading to robust, highly selective and sensitive sensors. As proof of concept, sensors were evaluated on the street specimens and clinically relevant samples and successfully validated using UPLC-MS. [ABSTRACT FROM AUTHOR]

• A MINA was developed for the determination of FB1 in maize. • NanoMIPs were used for recognising FB1. • The nanoMIPs production reduced time and costs, compared to antibody production. • MINA has shown high correlation with ELISA and HPLC. Fumonisin B1 (FB1) is a carcinogenic mycotoxin produced by Fusarium species contaminating maize. At present, fumonisin determination is performed using costly and demanding chromatography techniques or immunoassays. Recently, a molecularly imprinted polymer nanoparticles (nanoMIPs) – based assay (MINA) has been developed for FB1 detection. Herein, we have applied MINA for the determination of FB1 in naturally contaminated maize samples and results were compared with those obtained with ELISA and a reference HPLC method (AOAC No. 2001.04). The nanoMIPs as a recognition element mimicking antibodies used in ELISA were produced by solid phase synthesis and used in MINA for FB1 determination in 53 maize samples. As a result, 18 maize samples were contaminated with FB1 at levels higher than 0.25 mg/kg. Fumonisin concentrations from samples measured by MINA were well correlated with those using ELISA and HPLC. Therefore, MINA could be used as an alternative technique for FB1 determination in maize. [ABSTRACT FROM AUTHOR]