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Phosphodiester hydrogels offer a wide range of fascinating properties. Not only do they exhibit excellent hemocompatibility and cellular compatibility, they also show a remarkable resistance to protein adsorption, thereby limiting the foreign body response. In this work, phosphodiester‐crosslinked hydrogels are produced by a simple free‐radical polymerization of a phosphotriester crosslinker. In a second step, this material is transformed to the phosphodiester, by heating it up to 60 °C in phosphate‐buffered saline. Compared to earlier methods, there is no need for acids, bases, or oxidizing agents to achieve this final conversion to the phosphodiester. This method thus reduces the risk to damage or degrade any sensitive biomolecules that might be of interest to tissue engineers, such as various growth factors or other proteins. The phosphotriester crosslinker is readily synthesized out of common laboratory chemicals in multigram quantities with good yield and easy workup and purification. [ABSTRACT FROM AUTHOR]

The scope of the presented research orientates itself towards the development of a Molecularly Imprinted Polymer (MIP)-based dye displacement assay for the colorimetric detection of the antibiotic amoxicillin in aqueous medium. With this in mind, the initial development of an MIP capable of such a task sets focus on monolithic bulk polymerization to assess monomer/crosslinker combinations that have potential towards the binding of amoxicillin. The best performing composition (based on specificity and binding capacity) is utilized in the synthesis of MIP particles by emulsion polymerization, yielding particles that prove to be more homogenous in size and morphology compared to that of the crushed monolithic MIP, which is an essential trait when it comes to the accuracy of the resulting assay. The specificity and selectivity of the emulsion MIP proceeds to be highlighted, demonstrating a higher affinity towards amoxicillin compared to other compounds of the aminopenicillin class (ampicillin and cloxacillin). Conversion of the polymeric receptor is then undertaken, identifying a suitable dye for the displacement assay by means of binding experiments with malachite green, crystal violet, and mordant orange. Once identified, the optimal dye is then loaded onto the synthetic receptor, and the displaceability of the dye deduced by means of a dose response experiment. Alongside the sensitivity, the selectivity of the assay is scrutinized against cloxacillin and ampicillin. Yielding a dye displacement assay that can be used (semi-)quantitatively in a rapid manner. [ABSTRACT FROM AUTHOR]

• The review aims to summarize recent commercially interesting innovations in MIP-based sensor design. • In addition to sensors, commercially viable assays based on MIPs are analysed and recent advances are summarized and discussed. • The review also analyses how commercial MIP companies could contribute to a next step in the commercialization of MIP-based detection systems. • The review contains a critical analysis and discussion on MIP-based sensors and assay commercialization as well as an outlook/recommendation for the future. Molecularly imprinted polymers (MIPs) have emerged over the past few decades as interesting synthetic alternatives due to their long-term chemical and physical stability and low-cost synthesis procedure. They have been integrated into many sensing platforms and assay formats for the detection of various targets, ranging from small molecules to macromolecular entities such as pathogens and whole cells. Despite the advantages MIPs have over natural receptors in terms of commercialization, the striking success stories of biosensor applications such as the glucose meter or the self-test for pregnancy have not been matched by MIP-based sensor or detection kits yet. In this review, we zoom in on the commercial potential of MIP technology and aim to summarize the latest developments in their commercialization and integration into sensors and assays with high commercial potential. We will also analyze which bottlenecks are inflicting with commercialization and how recent advances in commercial MIP synthesis could overcome these obstacles in order for MIPs to truly achieve their commercial potential in the near future. [ABSTRACT FROM AUTHOR]

Antimicrobial resistance (AMR) poses a significant threat to global health, powered by pathogens that become increasingly proficient at withstanding antibiotic treatments. This review introduces the factors contributing to antimicrobial resistance (AMR), highlighting the presence of antibiotics in different environmental and biological matrices as a significant contributor to the resistance. It emphasizes the urgent need for robust and effective detection methods to identify these substances and mitigate their impact on AMR. Traditional techniques, such as liquid chromatography-mass spectrometry (LC-MS) and immunoassays, are discussed alongside their limitations. The review underscores the emerging role of biosensors as promising alternatives for antibiotic detection, with a particular focus on electrochemical biosensors. Therefore, the manuscript extensively explores the principles and various types of electrochemical biosensors, elucidating their advantages, including high sensitivity, rapid response, and potential for point-of-care applications. Moreover, the manuscript investigates recent advances in materials used to fabricate electrochemical platforms for antibiotic detection, such as aptamers and molecularly imprinted polymers, highlighting their role in enhancing sensor performance and selectivity. This review culminates with an evaluation and summary of commercially available and spin-off sensors for antibiotic detection, emphasizing their versatility and portability. By explaining the landscape, role, and future outlook of electrochemical biosensors in antibiotic detection, this review provides insights into the ongoing efforts to combat the escalating threat of AMR effectively. [ABSTRACT FROM AUTHOR]

Nutrition and health claims can help translate nutrition and health recommendations into easier-to-access messages at the point of sale. National Food Composition Databases (FCDBs) are the main and most widely available source of nutrient information for unpacked foods, such as fruits and vegetables. This paper outlines the variability of the nutrient content in fresh fruits and vegetables from FCDBs, both in the Euregio Meuse-Rhine and in the top eight European producers. All to analyse whether these variations would be translated into practical differences in the nutrition and health claims allowed in these European countries. The results show that vitamins presented the highest variability, particularly vitamin C, and differences were more prominent for vegetables than for fruits. These differences also extended to the use of claims between countries, particularly for folate and vitamin C. Moreover, the lack of item representation at the cultivar level affected the regional representativeness of fresh produce varieties and derived used of nutrition and health claims. Finally, widely available, and cost-efficient nutrient composition sources could economically benefit small and middle-scale producers to sustain nutrition and health claims on their products. • Vitamins concentrations differ by country, being vitamin C the most variable. • Compositional variability is reflected in the use of claims between countries. • Databases lack data on cultivar, practices, seasonality, and production region. • Databases constitute key resources for producers to sustain food claims. [ABSTRACT FROM AUTHOR]

By clearing GABA from the synaptic cleft, GABA transporters (GATs) play an essential role in inhibitory neurotransmission. Consequently, in vivo visualization of GATs can be a valuable diagnostic tool and biomarker for various psychiatric and neurological disorders. Not surprisingly, in recent years several research attempts to develop a radioligand have been conducted, but so far none have led to suitable radioligands that allow imaging of GATs. Here, we provide an overview of the radioligands that were developed with a focus on GAT1, since this is the most abundant transporter and most of the research concerns this GAT subtype. Initially, we focus on the field of GAT1 inhibitors, after which we discuss the development of GAT1 radioligands based on these inhibitors. We hypothesize that the radioligands developed so far have been unsuccessful due to the zwitterionic nature of their nipecotic acid moiety. To overcome this problem, the use of non-classical GAT inhibitors as basis for GAT1 radioligands or the use of carboxylic acid bioisosteres may be considered. As the latter structural modification has already been used in the field of GAT1 inhibitors, this option seems particularly viable and could lead to the development of more successful GAT1 radioligands in the future. [ABSTRACT FROM AUTHOR]

Impaired expression of GABA transporters (GATs) is closely related to the pathogenesis of among others Parkinson's disease and epilepsy. As such, lipophilic nipecotic acid analogs have been extensively studied as GAT1-addressing drugs and radioligands but suffer from limited brain uptake due to the zwitterionic properties of the nipecotic acid moiety. Bioisosteric replacement of the carboxylic acid group is a promising strategy to improve the brain uptake, though it requires knowledge on the binding of these isosteres to GAT1. To screen nipecotic acid isosteres for their affinity to GAT1 in a time- and cost-effective manner, this research aims to develop a molecular imprinted polymer (MIP) that mimics the natural binding site of GAT1 and can act as an alternative screening tool to the current radiometric and mass spectrometry cellular-based assays. To this end, a nipecotic acid MIP was created using the electropolymerization of ortho -phenylenediamine (oPD) by cyclic voltammetry (CV). The optimization of the generated receptor layer was achieved by varying the scan rate (50–250 mV/s) and number of CV cycles (5–12), yielding an optimized MIP with an average imprinting factor of 2.6, a linear range of 1–1000 n m , and a theoretical LOD of 0.05 n m , as analyzed by electrical impedance spectroscopy (EIS). Selectivity studies facilitated the investigation of major binding interactions between the MIP and the substrate, building an experimental model that compares characteristics of various analogs. Results from this model indicate that the substrate carboxylic acid group plays a more important role in binding than an amine group, after comparing the binding of cyclohexanecarboxylic acid (average IF of 1.7) and piperidine (average IF of 0.46). The research culminates in a discussion regarding the feasibility of the in vitro model, comparing the synthetic system against the biological performance of GAT1. Thus, evaluating if it is possible to generate a synthetic GAT1 mimic, and if so, provide directions for follow-up research. A nipecotic acid molecular imprinted polymer (MIP) was developed with a view to generating an artificial GAT1 mimic to allow in vitro screening of nipecotic acid bioisosteres. After selection, well-binding isosteres might be used to develop more viable GAT1-addressing drugs and radioligands. [Display omitted] • GAT1 mimic can allow time- and cost-effective screening of nipecotic acid isosteres. • A nipecotic acid molecular imprinted polymer was developed as artificial GAT1 mimic. • The developed synthetic system is compared against biological performance of GAT1. [ABSTRACT FROM AUTHOR]

The use of the veterinary tranquilizer xylazine as an adulterant poses a major health problem in the world. Involuntary consumption of this drug (e.g. spiked beverages and suicidal attempts) leads to loss of consciousness and even death. In this work, a probe for the fast, visual detection of xylazine in alcoholic beverages is proposed. The technology is based on xylazine-specific molecularly imprinted polymers that were loaded with methylene blue to generate a dye-displacement assay. The assay displayed high selectivity when evaluated against common compounds present in beverages. Optimal assay conditions were found at pH ≥ 7 and alcohol contents <15 v/v%. Furthermore, the assay was evaluated in a real gin and tonic sample and displayed a linear regime of 1.5–4 mM and a LOD of 1.36 mM. Implementation of the assay in a portable device resulted in a much faster xylazine detection (under 30 s) in a spiked gin & tonic sample. [Display omitted] • A colorimetry assay using molecularly imprinted polymers for the detection of xylazine in alcoholic beverages. • The assay showed high selectivity for xylazine and required minimal sample pretreatment. • The optimized assay detected xylazine in spiked gin and tonic samples within 4 min. • A dip-stick-like device was developed and tested for xylazine detection in gin and tonic, yielding positive results within 20 seconds. [ABSTRACT FROM AUTHOR]

[Display omitted] • Antibiotic resistance represents a crucial and pressing issue for food safety. • Tailor-made functional conjugated monomers can enhance MIPs sensitivity. • Au-SPEs represent an alternative for the rapid detection of streptomycin in food. • Fast and reliable electrochemical antibiotic detection is viable in milk samples. Antibiotic resistance is a global health threat, challenging traditional treatments and complicating the food safety process. This study introduces an electrochemical detection method for streptomycin sulfate, utilizing gold screen-printed electrodes (Au-SPE) functionalized via electropolymerization of a custom-made naphthalene diimide-based conjugated monomer (Th 2 -NDI-PIA). This modification creates specific binding sites for streptomycin, allowing rapid detection of the antibiotic. The sensor's response to different concentrations of streptomycin was studied via Differential Pulse Voltammetry (DPV) in a wide linear range from 10-13 M to 10-9 M, with a limit of detection (LoD) of 0.190 ± 0.005 pM. The imprinted electrode demonstrates selectivity to other antibiotics, but also to common interferents that can be found in milk such as lactose, glucose, riboflavin, and bisphenol A. Successful proof-of-principle in whole cow milk highlights the sensor's efficacy in detecting antibiotic residues in food samples, offering a promising alternative for a rapid and portable detection technique. [ABSTRACT FROM AUTHOR]

In laboratory environments, 3D printing is used for fast prototyping of assays and devices. Stereolithographic (SLA) 3D printers are proven to be the best choice for most researchers due to their small feature size, which is achieved by selectively curing liquid resin using a laser with a small focal point and then forming consecutive layers out of cured polymer. However, in microfluidic applications, where the limits of these machines are reached, the final results are influenced by many factors. In this work, the Form 2 SLA printer is tested to show how to achieve the best printing results for the creation of microfluidic channels. Several test structures are designed and printed with embedded and open channels in different orientations, sizes, and resins. Embedded channels significantly under perform when compared with open surface channels in terms of accuracy. Under the best printing conditions, 500 μm is the limit for embedded channels, whereas the open surface channels show good accuracy up to widths and depths of 250 μm. [ABSTRACT FROM AUTHOR]

Figure. Schematic representation of the concept. Aluminum chips are functionalized to allow grafting of molecularly imprinted polymer (MIP) receptor layers directly on the chip. Rebinding is analyzed by monitoring the thermal transport over the chip in time. • MIPs directly grafted onto aluminium substrates for the detection of new psychoactive substances (NPS). • Demonstration of HTM-based detection using surface grafted MIPs for the first time. • Selective discrimination between NPS and common adulterants. The use of Molecularly Imprinted Polymers (MIPs) as recognition elements in biosensing devices has increased over the past decade, with MIP-based receptor layers being combined with impedance, quartz crystal microbalance (QCM) and thermal readout methods such as the so-called "Heat-Transfer Method" (HTM). One of the main challenges in MIP-based biosensing is the production of uniformly covered, reproducible sensing layers. The potential of direct surface grafting of molecularly imprinted polymeric receptor layers (MIP-RL) to aluminum substrates was investigated in this work, offering an alternative more elegant methodology of MIP deposition opposed to previous methods introduced. Polished aluminum plates were hydroxylated and further silylated, thereby introducing functionality to the plates allowing for direct polymer grafting to the substrate surface. Various polymer compositions were studied, identifying the optimum composition for direct surface grafting and the detection of the New Psychoactive Substance (NPS) known as 2-methoxphenidine (2-MXP). Evaluation using HTM for each grafted MIP-RL determined the imprinting effect, selectivity and sensitivity of the polymeric layers, with a direct comparison being drawn to previously optimized MIP particles that have been deposited by means of a polydimethylsiloxane (PDMS) stamp being pressed into an adhesive polyvinyl chloride (PVC) layer. The results summarized in this study highlight the reproducibility, improved limit of detection (LoD), and feasibility of directly grafting polymeric layers to substrates, offering a more reliable tool in the routine analysis of samples. [ABSTRACT FROM AUTHOR]

Molecularly imprinted polymer (MIP)-based thermal sensing has proven to be a very interesting tool for diagnostic purposes. However, many fundamental phenomena are not yet fully understood. In the following study, MIPs are imprinted with the new psychoactive substance methoxphenidine (2-MXP). Thermal detection of this compound in water is demonstrated for the very first time and the effect of varying the adhesive layer composition on the performance of the sensor is analyzed. Three different polymers are used to create a uniform adhesive layer. The surface coverage of MIPs on each of the layers as well as the heat-transfer properties are studied. The results of the study indicate that the chips coated with poly(vinyl butyral-co-vinyl alcohol-co-vinyl acetate) display a higher surface coverage and a lower thermal resistance value. This results in an improved effect size and therefore improves dynamic range of the sensor. [ABSTRACT FROM AUTHOR]

Accurate and sensitive detection of bacteria is crucial in medicine for diagnosis and effective treatment of infectious diseases. Current state-of-the art methods consist of either traditional time consuming microbiological analysis or rapid, sensitive molecular techniques that require expensive readout equipment. In previous work, the authors of this paper combined synthetic bacteria receptors, so-called surface imprinted polymers (SIPs), with a novel thermal biosensor readout methodology for the detection of bacteria in urine. In this follow-up study, the potential of the method for application in urinary tract infection (UTI) diagnosis is further studied. The reproducibility of the method is assessed by expanding the study and analyzing the sensor's performance in urine samples obtained from four healthy adults. The samples are spiked with increasing concentrations of Escherichia coli to obtain different dose-response curves. The results of this study show that the method is reproducible over the studied population and variables such as age, gender and osmolality do not seem to influence the test. All results fall within the previously established dynamic range of 104-105 bacteriamL-1 which fits well within the diagnostic window of classical microbiological UTI tests. Further tests conducted on a urine sample 24 h after spiking illustrate the problem with traditional microbiology tests as the sensor response has significantly decreased due to the presence of a significant amount of dead bacteria in the day-old sample. These results confirm that fast, point-of-care analysis of fresh urine samples is advantageous over classic laborious techniques in terms of accurate diagnosis. [ABSTRACT FROM AUTHOR]

Highlights • Competitive binding between target and dye can be exploited for drug detection. • Dye-loaded drug receptors displace their dye upon exposure to drug solutions. • Displacement assay can be optimized by rational design of receptors and dyes. • Results can be quantified by absorption spectroscopy. • The assay can be used for identifying unknown powders as narcotics. Abstract In this work, a novel detection assay for the new psychoactive substance (NPS) 2-methoxiphenidine (2-MXP) and other diarylethylamines is introduced. The assay is based on the competitive displacement of dye molecules from molecularly imprinted polymers (MIPs) by the target molecule. The assay was fully characterized by studying the affinity of the MIP for six common dyes, expressed as the binding factor (BF). The results of this study indicate that the mathematical relationship between the BF of a dye and the imprinting factor (IF) for the target could be used for the prediction of the efficacy of the displacement assay. Dye-loaded MIP particles where incubated with the target, two adulterants and two legal pharmacological compounds. The target has a higher affinity for the MIP than the dye and displaces it out of the nanocavities of the receptor leading to a colour change in the filtrate that can be observed with the naked eye. Incubation of the MIP particles with the adulterants and legal medicines did not result in any observable change in absorbance. The robust, fast and low-cost nature of the assay, combined with its tailorable selectivity and generic nature, illustrate its potential as a pre-screening tool for the identification of narcotic substances in unidentified powders. [ABSTRACT FROM AUTHOR]

Surface detection of bacteria has been proven difficult and time‐consuming. Different recovery techniques yield varying numbers of bacteria. Subsequently, bacterial culturing, used for identification of these bacteria, will take several hours. In this article, the potential of a newly developed thermal biomimetic sensor for the detection of bacteria on surfaces is described. Previously this thermal biomimetic sensor has proven to be able to detect and quantify different bacteria in various liquid media such as buffer and spiked urine samples. In this article, laboratory surfaces are contaminated with increasing concentrations of Escherichia coli. Bacteria are recovered from the surfaces using commercially available swab rinse kits (SRK). A calibration curve is created by coating chips with surface‐imprinted polymers (SIPs), serving as synthetic bacteria receptors, and exposing them to increasing concentrations of E. coli. Next, concentrations of E. coli in the SRK buffer are measured and quantified. The results show that it is possible to detect E. coli recovered from surfaces. Although quantification has been proven difficult as the dynamic range of the sensor is relatively narrow and the bacterial load obtained by using SRK is low, the sensor is able to give an indication about the concentration present on the surface. The results in this article illustrate that the thermal biomimetic sensor is a fast, low‐cost, and label‐free device useful in surface detection of E. coli, and seems a promising tool for future on‐site bacterial detection. [ABSTRACT FROM AUTHOR]

The implementation of Molecularly Imprinted Polymers (MIPs) into sensing systems has been demonstrated abundantly over the past few decades. In this article, a novel application for an MIP-based thermal sensing platform is introduced by using the sensor to characterize the drug release kinetics of a nanoporous silver-organic framework. This Ag nanoporous matrix was loaded with acetylsalicylic acid (aspirin) which was used as a model drug compound in this study. The drug elution properties were studied by placing the nanoporous matrix in phosphate buffered saline solution for two days and measuring the drug concentration at regular time intervals. To this extent, an acrylamide-based MIP was synthesized that was able to detect aspirin in a specific and selective manner. Rebinding of the template to the MIP was analyzed using a thermal sensor platform. The results illustrate that the addition of aspirin into the sensing chamber leads to a concentration-dependent increase in the phase shift of a thermal wave that propagates through the MIP-coated sensor chip. After constructing a dose-response curve, this system was used to study the drug release kinetics of the nanoporous matrix, clearly demonstrating that the metalorganic framework releases the drug steadily over the course of the first hour, after which the concentration reaches a plateau. These findings were further confirmed by UV-Visible spectroscopy, illustrating a similar time-dependent release in the same concentration range, which demonstrates that the MIP-based platform can indeed be used as a low-cost straightforward tool to assess the efficacy of drug delivery systems in a lab environment. [ABSTRACT FROM AUTHOR]

• Screen-printed electrodes (SPEs) are functionalized via a facile polymer-imprinting protocol for the preparation of synthetic receptors for Escherichia coli. • The functionalized SPEs were employed for the thermal detection of E. coli for the first time. • The device is able to detect the model microorganism with a limit of detection of 180 CFU/mL. • The platform is validated in milk, demonstrating its suitability and reproducibility in comparison to experiments in buffer. Accurate and fast on-site detection of harmful microorganisms in food products is a key preventive step to avoid food-borne illness and product recall. In this study, screen-printed electrodes (SPEs) were functionalized via a facile strategy with surface imprinted polymers (SIPs). The SIP-coated SPEs were used in combination with the heat transfer method (HTM) for the real-time detection of Escherichia coli. The sensor was tested in buffer, with a reproducible and sensitive response that attained a limit of detection of 180 CFU/mL. Furthermore, selectivity was assessed by analyzing the sensor's response to C. sakazakii, K. pneumoniae and S. aureus as analogue strains. Finally, the device was successfully used for the detection of E. coli in spiked milk as proof-of-application, requiring no additional sample preparation. These results suggest the proposed thermal biosensor possesses the potential of becoming a tool for routine, on-site monitoring of E. coli in food safety applications. [ABSTRACT FROM AUTHOR]

This paper presents the application of the conducting polymer polypyrrole in a pressure sensitive sensor. Polypyrrole was electrodeposited on copper plates using phytic acid as a dopant and cross-linker. A combination of different polymerization durations and potentials were tested to find the polymerization conditions for thin polymer layers and homogenous surface coverage. The morphology of the surface of the polypyrrole films was examined with scanning electron microscopy to study the formation of hollow sphere beads. The polymer layers were sandwiched between two copper sheets to create pressure sensitive sensors and the piezo-resistive effect was tested. For this, increasing forces were applied to the sensors and the resistance was measured. It was found that the polypyrrole layers were pressure sensitive to pressures relevant for bruxism events and had a thickness that is suitable for application in a splint for the detection of awake bruxism. An SEM image of polypyrrole hollow sphere beads at 20 kV and 1000× magnification. [ABSTRACT FROM AUTHOR]

• Surface imprinted poly (urethane- co -urea) for the recognition of fecal indicator Escherichia coli. • Quantitative detection of the pathogen can be performed employing thermal and impedance readout platforms. • The thermal biomimetic sensor can be used for selective identification of the targeted bacteria against Staphylococcus aureus. • Potential application in food safety screening: detection of E. coli in milk. The incorporation of imprinted polymers (IP) into sensing devices has enabled the detection of a wide range of analytes going from molecules to whole cells. Biomimetic platforms for bacteria recognition possess the potential of being a low-cost and on-site testing technology for applications in food safety, where the accurate detection of pathogens is crucial for preventing disease. This work presents the optimization of a label-free thermal IP-based sensor for the detection of E. coli , a microorganism indicator of fecal contamination in drinking water and milk. By modifying the functional monomers employed in the synthesis of imprinted polyurethanes, the production process was sped up by a factor four. The receptor layers, which exhibited enhanced imprint surface-coverage, yielded in bacteria quantification at concentrations in the range of 1000 CFU/mL, an improvement of a full order of magnitude for the thermal sensor. Benchmarking of the results was performed with a commercial impedance analyzer, demonstrating the suitability of the receptors for electrochemical analysis. Furthermore, the results presented assess the selectivity of the thermal device against S. aureus. Finally, a proof of concept of the sensor in milk as complex sample is presented for the first time, confirming that the dynamic range and sensitivity of the device will suffice to detect fecal contamination of milk samples in resource-deprived settings. [ABSTRACT FROM AUTHOR]

The rapid sensing of drug compounds has traditionally relied on antibodies, enzymes and electrochemical reactions. These technologies can frequently produce false positives/negatives and require specific conditions to operate. Akin to antibodies, molecularly imprinted polymers (MIPs) are a more robust synthetic alternative with the ability to bind a target molecule with an affinity comparable to that of its natural counterparts. With this in mind, the research presented in this article introduces a facile MIP-based dye displacement assay for the detection of (±) amphetamine in urine. The selective nature of MIPs coupled with a displaceable dye enables the resulting low-cost assay to rapidly produce a clear visual confirmation of a target's presence, offering huge commercial potential. The following manuscript characterizes the proposed assay, drawing attention to various facets of the sensor design and optimization. To this end, synthesis of a MIP tailored towards amphetamine is described, scrutinizing the composition and selectivity (ibuprofen, naproxen, 2-methoxphenidine, quetiapine) of the reported synthetic receptor. Dye selection for the development of the displacement assay follows, proceeded by optimization of the displacement process by investigating the time taken and the amount of MIP powder required for optimum displacement. An optimized dose–response curve is then presented, introducing (±) amphetamine hydrochloride (0.01–1 mg mL−1) to the engineered sensor and determining the limit of detection (LoD). The research culminates in the assay being used for the analysis of spiked urine samples (amphetamine, ibuprofen, naproxen, 2-methoxphenidine, quetiapine, bupropion, pheniramine, bromopheniramine) and evaluating its potential as a low-cost, rapid and selective method of analysis. [ABSTRACT FROM AUTHOR]