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Charge (ion and electron)-transfer reactions at a liquid/liquid interface are critical processes in many important biological and chemical systems. An ion-transfer (IT) process is usually very fast, making it difficult to accurately measure its kinetic parameters. Nano-liquid/liquid interfaces supported at nanopipettes are advantageous approaches to study the kinetics of such ultrafast IT processes due to their high mass transport rate. However, correct measurements of IT kinetic parameters at nanointerfaces supported at nanopipettes are inhibited by a lack of knowledge of the nanometer-sized interface geometry, influence of the electric double layer, wall charge polarity, etc. Herein, we propose a new electrochemical characterization equation for nanopipettes and make a suggestion on the shape of a nano-water/1,2-dichloroethane (nano-W/DCE) interface based on the characterization and calculation results. A theoretical model based on the Poisson-Nernst-Planck equation was applied to systematically study how the electric double layer influences the IT process of cations (TMA

© 2023The present study proposes two unique systems using free radical-induced grafting reactions to combine Ag, chitosan (CS) and gallic acid (GA) into a single particulate nanostructure. GA-grafted-CS (GA-g-CS) was used to reduce Ag+ to Ag0, and producing Ag-GA-g-CSNPs (hybrid NPs I). Also, GA was grafted into CS–AgNPs, to form GA-g-CS AgNPs (hybrid NPs II). Although there were previous attempts to graft GA into CS, this is first time to graft GA into CS–AgNPs. The study aimed to enhance biocompatibility, antibacterial and antioxidant properties of CS–AgNPs via grafted GA. Grafting GA into CS–AgNPs was confirmed by UV–Vis, DLS, DSC/TGA, XRD, EDX and FTIR. The morphology and size of NPs were studied by TEM and SEM. The decrease of ζ-potential from +50 mV in CS-Ag NPs to +33 and + 29 mV, in the presented 2 nanoforms hybrid NPs I and II, respectively, is an indication for the successful GA graft. Among all samples, hybrid NPs II showed lower toxicity, higher antioxidant and antibacterial activity. The obtained results revealed that grafting GA to CS–AgNPs, as a new method to combine Ag, CS and GA in a uniparticulate structure, is a unique process which may deserve a more future consideration.

Carbon materials derived from marine waste have been drawing attention for supercapacitor applications. In this work, chitins from squid and prawn marine wastes were used as carbon precursors for further application as electrodes for energy storage devices. Chitins were obtained through a deproteinization method based on enzymatic hydrolysis as an alternative to chemical hydrolysis as commonly presented in the literature. The obtained porous carbons were characterized using a BET surface area analyzer to determine the specific surface area and pore size, as well as scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), Raman spectroscopy, attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), to characterize their morphology, composition, and structure. The electrochemical characterization was performed using a glassy carbon (GC) electrode modified with marine waste-based porous carbons as the working electrode through cyclic voltammetry and galvanostatic charge/discharge using ethaline, a choline chloride-based deep eutectic solvent (DES), as an eco-friendly and sustainable electrolyte. Squid and prawn chitin-based carbons presented a surface area of 149.3 m2 g−1 and 85.0 m2 g−1, pore volume of 0.053 cm3 g−1 and 0.029 cm3 g−1, and an associated specific capacitance of 20 and 15 F g−1 at 1 A g−1, respectively. Preliminary studies were performed to understand the effect of -OH groups on the chitin-based carbon surface with DES as an electrolyte, as well as the effect of aqueous electrolytes (1 mol L−1 sulphuric acid (H2SO4) and 1 mol L−1 potassium hydroxide (KOH)) on the capacitance and retention of the half-cell set up. It is provided, for the first time, the use of chitin-based carbon materials obtained through a one-step carbonization process combined with an eco-friendly DES electrolyte for potential application in energy storage devices.

The integration of bacteriophages, a particular class of viruses that specifically infect bacteria and archaea, in biosensors for the monitoring of pathogens in foods and beverages is highly desirable. To this end, an increasing focus has been set on the exploration of covalent and physical methods for the immobilization of phages on solid surfaces. This work investigates the electrostatic assembly of tailed phages, specifically anti-Listeria monocytogenes P100 phages, on an ultrathin self-assembled monolayer (SAM) of 11-amino-1-undecanethiol (AUT). The cationic properties of AUT may allow for the electrostatic capture of P100 in a capsid-down fashion, thus, exposing the specific receptor-binding proteins on their tails to the corresponding pathogens in analytical samples. The physical properties of immobilized phages have been studied using AFM, SEM, and electrochemical techniques, providing insight into the orientation of the phages and revealing that the pH plays a remarkable role in the morphology and charge transfer behavior of the adsorbed films. Overall, this research portrays SAMs of amino-akylthiols as a valid platform for the oriented immobilization of bacteriophages on surfaces for electroanalytical purposes.

17 pages, 11 figures, 3 tables.-- Open access, Waste, in particular, biowaste, can be a valuable source of novel carbon materials. Renewable carbon materials, such as biomass-derived carbons, have gained significant attention recently as potential electrode materials for various electrochemical devices, including batteries and supercapacitors. The importance of renewable carbon materials as electrodes can be attributed to their sustainability, low cost, high purity, high surface area, and tailored properties. Fish waste recovered from the fish processing industry can be used for energy applications and prioritizing the circular economy principles. Herein, a method is proposed to prepare a high surface area biocarbon from glycogen extracted from mussel cooking wastewater. The biocarbon materials were characterized using a Brunauer–Emmett–Teller surface area analyzer to determine the specific surface area and pore size and by scanning electron microscopy coupled with energy-dispersive X-ray analysis, Raman analysis, attenuated total reflectance Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy. The electrochemical characterization was performed using a three-electrode system, utilizing a choline chloride-based deep eutectic solvent (DES) as an eco-friendly and sustainable electrolyte. Optimal time and temperature allowed the preparation of glycogen-based carbon materials, with a specific surface area of 1526 m2 g–1, a pore volume of 0.38 cm3 g–1, and an associated specific capacitance of 657 F g–1 at a current density of 1 A g–1, at 30 °C. The optimal material was scaled up to a two-electrode supercapacitor using a DES-based solid-state electrolyte (SSE@DES). This prototype delivered a maximum capacitance of 703 F g–1 at a 1 A g–1 of current density, showing 75% capacitance retention over 1000 cycles, delivering the highest energy density of 0.335 W h kg–1 and power density of 1341 W kg–1. Marine waste can be a sustainable source for producing nanoporous carbon materials to be incorporated as electrode materials in energy storage devices, This work was financially supported by the FCT under Research Grants UIDB/00081/2020–CIQUP, LA/P/0056/2020 (IMS), and H2Innovate NORTE-01-0145-FEDER-000076. This work was supported by the Romanian Ministry of Research, Innovation and Digitalization, Romania, under JINR-RO Project no. 91 Code Theme 04–4–1133–2018/2023, grant no. 37/2021, and ECSEL-H2020 projects: PIn3S Contract no. 10/1.1.3H/03.04.2020 Code MySMIS 135127 and BEYOND5 Contract no. 12/1.1.3H/31.07.2020 Code MySMIS 136877. J.A.V. and J.V. thank Xunta de Galicia (Grupos de Potential Crecimiento, IN607B 2021/11) for financial support . A.T.S.C.B. thanks the scholarship awarded by FCT with reference No. 2021.04783.BD and the Schwäbisch Gmünd Scientific Exchange Grant awarded by the European Academy of Surface Technology. R.C. thanks FCT for funding through the program DL 57/2016–Norma transitória (SFRH/BPD/89752/2012)

The design and synthesis of artificial receptors based on molecular imprinting (MI) technology for the development of a new MIP-based biosensor for detection of the stress biomarker α-amylase in human saliva in point-of-care (PoC) applications is described in this work. The portable electrochemical devices for monitoring α-amylase consists of cost-effective and disposable gold screen-printed electrodes (AuSPEs). To build the electrochemical device, the template biomolecule was firstly immobilized directly over the working area of the gold chip previously activated with a self-assembled monolayer (SAM) of cysteamine (CA). Then, pyrrole (Py) monomer was selected as building block of a polymeric network prepared by CV electropolymerization. After the electropolymerization process, the enzyme was removed from the polymer film in order to build the specific recognition sites for the target enzyme. The MIP biosensor showed a very wide linear concentration range (between 3.0 × 10−4 to 0.60 mg mL−1 in buffer solution and between 3.0 × 10−4 to 3.0 × 10−2 mg mL−1 in human saliva) and low detection levels were achieved (LOD &lt, 3.0 × 10−4 mg mL−1) using square wave voltammetry (SWV) as the electroanalytical technique.

The study of sensing materials to the detection of carbon dioxide (CO2) was achieved using p-nitrophenol (pNPh) as a colorimetric indicator. The sensing material was polymerized (NPLn), functionalized with 3-triethoxysilyl propyl isocyanate (IPTES) which sensitivity was tested in the form of a membrane as is and encapsulated in hollow silica nanoparticles. The sensing membranes were tested in a closed gas system comprising very precise flow controllers to deliver different concentrations of CO2 (vs. N2). The combination of the sensing membranes with multimode optical fibers and a dual-wavelength diode (LED) allows the measurement of the CO2 through the analysis of the induced absorbance changes with a self-referenced ratiometric scheme. The analysis of the sensing materials have shown significant changes in their chemical and physical properties and the results attest these materials with a strong potential for assessing CO2 dynamics in environmental, medical, and industrial applications.

This work reports the role of different dispersants, namely, polyethylene glycol (PEG 200 2%), ethylene glycol 5%, ethanol 2%, dimethyl sulfoxide (DMSO 5%), and polyvinyl alcohol (PVA 5%) in the toxicity profile of several commercial nanomaterials (NM), such as hydrophilic and hydrophobic TiO2, hydrophilic SiO2, SiO2 in aqueous suspension (aq), and ZnO towards the bioluminescent bacterium Aliivibrio fischeri. The majority of NM showed tendency to form agglomerates in the different dispersants. Although some particle agglomeration could be detected, DMSO at 5% was the best dispersant for hydrophobic TiO2 NM while PVA at 5% was the most effective dispersant for the other types of NM. Average size was not the most relevant aspect accounting for their toxicity. A remarkable reduction in average size was followed by a decrease in NM toxicity, as demonstrated for SiO2 aq. in PVA 5%. Contrarily, despite of high particle agglomeration, ZnO NM showed a higher toxicity to bacteria when compared with other tested NM. Independently of the average particle size or surface charge, the dispersant either enhanced the toxicity to bacteria or acted as physical barrier decreasing the NM harmful effect to A. fischeri.

The synthesis of noble metal nanoparticles (i.e., silver and gold) for electrochemical applications has been widely studied using mainly wet synthesis chemical methods or electrochemical deposition methods. In this work, we propose a single-step flash photochemical method for synthesizing noble metal nanoparticles (i.e., silver, gold, and Au:Ag) in solution for electrochemical applications. The method is based on the intense pulsed radiation emitted from a xenon flashlamp, which induce the reduction of metal cations in solution to form metallic nanoparticles. The present method is based on the selective light absorption of the metal precursor salts combined with the decomposition of polyvinylpyrrolidone added to the solution. This approach can be termed as flash light synthesis.

A new (bio)sensing platform based on differential refractometric measurements was developed. The sensing scheme is based on the combination LPFGs/MIP/NIP, involving a dual channel system for real-time compensation of non-specific interactions. The correction system improves the sensor behavior by reducing the response to interferents by 30%.

The aim of the present study was to investigate the eco-cytotoxicity of several forms of nanomaterials (NM), such as nano-CuO, nano-TiO2, nano-SiO2 and nano-ZnO, on different aquatic species (Raphidocelis subcapitata, Daphnia magna and Lemna minor) following standard protocols and on human cell lines (Caco-2, SV-80, HepG2 and HaCaT). Predicted no-effect concentrations (PNEC) or hazard concentrations for 5% of the species (HC5) were also estimated based on the compilation of data available in the literature. Most of the NM agglomerated strongly in the selected culture media. For the ecotoxicity assays, nano-CuO and nano-ZnO even in particle agglomeration state were the most toxic NM to the freshwater organisms compared to nano-TiO2 and nano-SiO2. Nano-ZnO was the most toxic NM to R. subcapitata and D. magna, while nano-CuO was found to be very toxic to L. minor. Nano-CuO was very toxic to Caco-2 and HepG2 cells, particularly at the highest tested concentrations, while the other NM showed no toxicity to the different cell lines. The HC5 and PNEC values are still highly protective, due to data limitations. However, the present study provides consistent evidence of the potential risks of both nano-CuO and nano-ZnO against aquatic organisms and also their effects on public health.

The urgent need to reduce the consumption of fossil fuels drives the demand for renewable energy and has been attracting the interest of the scientific community to develop materials with improved energy storage properties. We propose a sustainable route to produce nanoporous carbon materials with a high−surface area from commercial graphite using a dry ball−milling procedure through a systematic study of the effects of dry ball−milling conditions on the properties of the modified carbons. The microstructure and morphology of the dry ball−milled graphite/carbon composites are characterized by BET (Brunauer–Emmett–Teller) analysis, SEM (scanning electron microscopy), ATR−FTIR (attenuated total reflectance–Fourier transform infrared spectroscopy) and Raman spectroscopy. As both the electrode and electrolyte play a significant role in any electrochemical energy storage device, the gravimetric capacitance was measured for ball−milled material/glassy carbon (GC) composite electrodes in contact with a deep eutectic solvent (DES) containing choline chloride and ethylene glycol as hydrogen bond donor (HBD) in a 1:2 molar ratio. Electrochemical stability was tracked by measuring charge/discharge curves. Carbons with different specific surface areas were tested and the relationship between the calculated capacitance and the surface treatment method was established. A five−fold increase in gravimetric capacitance, 25.27 F·g−1 (G40) against 5.45 F·g−1, was found for commercial graphene in contact with DES. Optimal milling time to achieve a higher surface area was also established.

This work reports the development of a simple and rapid electrochemical immunosensor for the determination of breast cancer biomarker Cancer Antigen 153 (CA153). Disposable and cost-effective chips, consisting of gold screen-printed electrodes (AuSPEs), were used to develop the portable electrochemical devices for monitoring the biomarker in point-of-care (PoC), under clinical context. The biosensor preparation consisted of two simple steps. First, a self-assembled monolayer (SAM) of mercaptosuccinic acid (MSA) was formed at the AuSPE surface. Then, the CA153 antibody was covalently bound to the carboxylic groups standing at the electrode surface using EDC/NHS chemistry. The performance of the developed immunosensor was evaluated by assessing the sensor sensitivity, linear response interval, selectivity and detection limit (LOD). The developed immunosensor provided a wide linear concentration range (from 1.0 to 1000UmL1) and low detection levels were achieved (LOD of 0.95UmL1), enabling the sensitive detection of the cancer biomarker at clinically relevant levels, using square wave voltammetry (SWV) as electroanalytical technique. Moreover, selectivity studies performed against other cancer biomarkers (CA 125 and CA 199) revealed that the antibody has high selectivity for CA15-3 antigen. The immunosensor was applied to the quantification of CA15-3 in artificial serum samples with satisfactory results., This research had the financial support of FCT (Fundação para a Ciência e Tecnologia) and co-financed by the European Union (FEDER funds) under the Partnership Agreement PT2020, Research Grants Pest-C/QUI/UIDB/00081/2020 (CIQUP) and NORTE-01-0247-FEDER-017834 (project RamSERS). J.A. Ribeiro (ref. SFRH/BPD/105395/2014) and C.M. Pereira (ref. SFRH/BSAB/150320/2019) acknowledge FCT under the QREN – POPH – Advanced Training, subsidized by European Union and national MEC funds., info:eu-repo/semantics/publishedVersion

Molecular dynamics simulations of the electrical double layer at electrode–ionic liquid interfaces allow for molecular level interpretation of the interfacial phenomena and properties, such as differential capacitance (C). In this work, we have simulated an ionic liquid – 1-butyl-3-methylimidazolium hexafluorophosphate – at three gold surfaces, namely: Au(100), Au(110), and Au(111) surfaces. Atomic corrugation of the gold surface leads to higher C values due to the rapprochement of the surface and electrolyte charge planes. Likewise, by accounting for the shift of surface charge plane position towards the electrolyte also results in higher C values. The presented insight shows that a simple correction to the simulation data improves the agreement with the experimental data.

In this work, we describe an innovative methodology based on combined surface plasmon resonance (SPR) and electrochemical responses (eSPR) in the same immunoassay for screening CA 153 cancer biomarker with high sensitivity (and selectivity), in a very simple, label-free, accurate, and fully automated manner. Detection was achieved by performing two simple steps. In the first step, direct SPR was used to monitor CA 153 interaction with surface immobilized antibody. Two linear response ranges were obtained and the detection limit achieved is poor (LOD of 21 U mL1). However, in the second detection step, electrochemical measurements at the SPR gold surface were performed to measure the decrease of redox probe peak current upon antigenantibody interaction, providing a suitable amplification strategy to lower detection levels of CA 153 (LOD of 0.0998 U mL1), without the need of additional complex and/or expensive amplification steps to enhance the sensitivity. Moreover, selectivity studies were performed against other common cancer biomarkers and the results showed that the eSPR immunosensor is selective for the CA 153 protein. Finally, the clinical applicability of the developed eSPR biosensing methodology was successfully applied to detect CA 153 in human serum samples at clinically relevant levels due to the high sensitivity of electrochemical readout. The same concept may be further extended to other proteins of interest., This research had the financial support of FCT (Fundaca̧õ para a Ciencia e Tecnologia) and co ̂ financed by the European Union (FEDER funds) under the Partnership Agreement PT2020, Research Grants Pest-C/QUI/UIDB/00081/2020 (CIQUP) and NORTE-01-0247-FEDER-017834 (project RamSERS). J.A.R. (ref SFRH/BPD/105395/2014) and C.M.P. (ref SFRH/BSAB/150320/2019) acknowledge FCT under the QREN − POPH − Advanced Training, subsidized by European Union and national MEC funds. We thank BioMark/ISEP researchers Felismina Moreira and Joana Guerreiro for all the support to perform the ellipsometry measurements, info:eu-repo/semantics/publishedVersion

The aim of this work is to quantify the evolution of the various noncovalent interparticle interactions in the binary mixtures of imidazolium-based ionic liquids (ILs) with perfluorinated anions, hexafluorophosphate (C4mimPF6), bis(fluorosulfonyl)imide (C4mimNTf2), and tris(pentafluoroethyl)trifluorophosphate (C4mimFAP), and deep eutectic solvents (DESs), composed by choline chloride (ChCl), and ethylene- (EG) and propylene glycol (PG) molecules. For this purpose, by using combined molecular dynamics and density functional theory methodology, we analyze the most important intermolecular, interionic, and ion-molecular hydrogen bonding interactions in ILs and DESs. We found that the addition of FAP− to a mixture enhances the nonpolar domain segregations and weakens the hydrogen-bond network. It was confirmed that H2-site is the most prone to cation–anion interactions, whereas in the binary mixtures of ILs two anions compete for the most acidic hydrogen of imidazolium ring. Nonetheless, most of the hydrogen bonds in the studied IL mixtures are rather weak and can be referred to as “hydrogen-bond-like interactions.” The FAP-anion forms notably less hydrogen-bond-like interactions and only in neat IL or in FAP-rich regions of IL mixtures, stabilizing the ion pair mostly electrostatically. For the DES mixtures, it was established that ethaline-2 (molar ratio of ChCl and EG is 1:2) does not contain any real hydrogen bonds. Propeline (DES-based on ChCl and PG), however, presents weak hydrogen-bond formation between cation and anion and medium hydrogen-bond formation between anion and PG molecule.

Metal and alloys electrodeposition from aqueous electrolytes is restricted due to the narrow electrochemical window and hydrogen evolution. To overcome these disadvantages, over the past years, ionic liquids (ILs) and deep eutectic solvents (DES) based on choline chloride have been successfully applied for the electrodeposition of different metals.Tin (Sn) layers applied to automotive or decorative plating are thought of as ecological alternatives to exchange lead and nickel/chromium coatings. Over the past few years, the attention drawn by metallic alloys and composites, namely Sn alloys (nickel, indium, copper, zinc…) and Sn-carbon materials composites, has increased due to the possibility of applying these materials as anodes for lithium-ion batteries.This review will highlight the leading research regarding the electrodeposition of Sn and several alloys and carbon composites, emphasizing the morphological changes of the alloy combinations using DESs as electrolytes.

Mesoporous sorbent composites, evolving from previous work on microporous composites of polyanionic polysaccharides were developed with the purpose of increasing the sorptive features of the materials. Using the widely successful classical surfactant micelle approach, it was observed, in this particular case, that the composites remained essentially microporous. The alternative consisted on the application of deep eutectic solvents (DES). The most common DES (choline chloride + neutral hydrogen bond donor), were tested because of their advantages over other possibilities such as imidazolium-based ionic liquids: lower cost, easy in-house preparation, safe constituents and water stability and solubility. Possible mechanisms underlying the observed mesoporosity were discussed. The surface area ranged between 76 and 267 m2/g and the average pore size was in the range 3–5 nm. DES had not a negative effect on synthesis yields and, in the case of fucoidan, composites bearing a higher content of the biopolymer were produced. As a consequence and in line with the initial expectations these new composites revealed highly enhanced Pb (II) sorptive features comparatively to their microporous predecessors: chondroitin sulfate composites - up to a 5 fold capacity enhancement; fucoidan composites- up to a 3.5 fold capacity enhancement. The highest capacity was observed for the fucoidan composite prepared with choline chloride-ethyleneglycol DES, 79 mg Pb (II)/g, which is slightly above the highest value (77 mg Pb (II)/g) found in the literature for Pb (II) sorbents based on polysaccharides, sol-gels or their composites.

International audience; The air–ionic liquid interface for a series of ionic liquids involving imidazolium cations [Cnmim] with different alkyl chain lengths (n = 2, 4, 6, 8, 10, and 12) and the same [NTf2] imide anion has been studied by polarization-resolved second harmonic generation (SHG). An increase as a function of the alkyl chain length of the orientational parameter reveals the increasing ordering of the air–pure ionic liquid interfaces although it is not possible to disentangle the change in mean tilt angle from a change in the tilt angle probability distribution width. Besides, the study of the air–mixed ([C12mim])x([C2mim])1–x[NTf2] ionic liquid interface clearly demonstrates the interfacial nonideality of the mixed ionic liquids. The long alkyl chain cation perturbs the interface as seen from the orientational parameter and displaces the short alkyl chain one for bulk mixture contents as low as 10%. At higher long alkyl chain cation bulk mixture contents, the interface behaves close to a pure long alkyl chain ionic liquid.

The impact of fullerene side chain functionalization with thiophene and carbazole groups on the device properties of bulk-heterojunction polymer:fullerene solar cells is discussed through a systematic investigation of material blends consisting of the conjugated polymer poly[(5,6-difluoro-2,1,3-benzothiadiazol-4,7-diyl)-alt-(3,3&rsquo, &rsquo, di(2-octyldodecyl)-2,2&rsquo, 5&rsquo, 2&rsquo, quaterthiophen-5,5&rsquo, diyl)] (PffBT4T-2OD) as donor and C60 or C70 fulleropyrrolidines as acceptors. The photovoltaic performance clearly depended on the molecular structure of the fulleropyrrolidine substituents although no direct correlation with the surface morphology of the photoactive layer, as determined by atomic force microscopy, could be established. Although some fulleropyrrolidines possess favorable lowest unoccupied molecular orbital levels, when compared to the standard PC71BM, they originated OPV cells with inferior efficiencies than PC71BM-based reference cells. Fulleropyrrolidines based on C60 produced, in general, better devices than those based on C70, and we attribute this observation to the detrimental effect of the structural and energetic disorder that is present in the regioisomer mixtures of C70-based fullerenes, but absent in the C60-based fullerenes. These results provide new additional knowledge on the effect of the fullerene functionalization on the efficiency of organic solar cells.

l -tyrosine controlled release systems, based on imprinted polymers radically polymerized in modified organic solvents (dimethyl sulfoxide and methanol) were developed. A set of copolymers synthesized with different functional monomers and the crosslinker ethylene glycol dimethylacrylate were evaluated regarding both the imprinting and controlled release features. Those prepared in modified-DMSO were mesoporous (surface area ranging 370–690 m2/g) but not the ones prepared in modified methanol with the exception of the imprinted polymer prepared with the monomer vinylbenzoic acid (209 m2/g). The swelling degree ranged 32 to 64% and appeared to be mostly dependent on the functional group employed in the synthesis of the polymers. When tested in dynamic mode a clear imprinting effect has been observed in some of the imprinted polymers. However, selectivity for l -Tyr against similar compounds could not be found in these conditions. Selectivity could be observed when carrying out the isothermal analysis, with selectivity factors up to 2.7. A few polymers exhibited also other remarkable features such as high l -Tyr load capacity (up to 253 mg l -Tyr/g) and large binding strength (up to 55 Lmmg(1-m))/g). Therefore, imprinted polymers capable of a selective sorption of l -Tyr upon equilibration, containing stronger binding sites for l -Tyr, appeared promising vehicles for its controlled release. In fact, the release assays with l -Tyr impregnation by adsorption, showed profiles corresponding to controlled release systems, with high yield (40–50%) and continuous release (up to at least 7 h). In addition, release mechanisms recommended for controlled release systems were deduced from kinetic data fitting to the Korsmeyer and Order 0 models.

Artificial receptors that mimic their natural biological counterparts have several advantages, such as lower production costs and increased shelf-life stability/versatility, while overcoming the ethical issues related to raising antibodies in animals. In this work, the proposed tailor-made molecularly imprinted polymer (MIP)-allergen receptors aimed at substituting or even transcending the performance of biological antibodies. For this purpose, a MIP was proposed as an artificial antibody for the recognition of hazelnut Cor a 14-allergen. The target protein was grafted onto the conducting polypyrrole receptor film using gold screen-printed electrodes (Au-SPE). The electrochemical assessment presented a linear response for the dynamic range of 100 fg mL−1-1 μg mL−1 and a LOD of 24.5 fg mL−1, as determined by square wave voltammetry from the calibration curves prepared with standards diluted in phosphate buffer. Surface plasmon resonance (SPR) was used as a secondary transducer to evaluate the performance of the Cor a 14-MIP sensor, enabling a linear dynamic range of 100 fg mL−1- 0.1 μg mL−1 and a LOD of 18.1 fg mL−1. The selectivity of the tailored-made Cor a 14-MIP was tested against potentially cross-reactive plant/animal species based on the rebinding affinity (Freundlich isotherm-KF) of homologues/similar proteins, being further compared with custom-made polyclonal anti-Cor a 14 IgG immunosensor. Results evidenced that the MIP mimics the biorecognition of biological antibodies, presenting higher selectivity (only minor cross-reactivity towards walnut and Brazil nut 2S albumins) than the Cor a 14/anti-Cor a 14 IgG immunosensor. The application of electrochemical Cor a 14-MIP sensor to model mixtures of hazelnut in pasta enabled quantifying hazelnut down to 1 mg kg−1 (corresponding to 0.16 mg kg−1 of hazelnut protein in the matrix). To the best of our knowledge, Cor a 14-MIP is the first sensor based on an artificial/synthetic biorecognition platform for the specific detection of hazelnut allergens, while presenting high-performance parameters with demonstrated application in food safety management.

Two immunosensors were advanced to target hazelnut Cor a 14 based on electrochemical and optical transduction. Both approaches were developed with two types of custom-made antibodies, namely anti-Cor a 14 IgG (rabbit) and anti-Cor a 14 IgY (hen’s egg) targeting the Cor a 14 allergen. Antibody immobilisation was performed via EDC/NHS onto disposable screen-printed electrodes. The detection limit (LOD) of the electrochemical immunoassay for Cor a 14 was 5-times lower than the optical, being down to 0.05 fg mL−1 with a dynamic range of 0.1 fg mL−1 to 0.01 ng mL−1. Antibody selectivity was verified against non-target 2S albumins (potential cross-reactive plant species). Anti-Cor a 14 IgY exhibited the best specificity, presenting minor cross-reactivity with peanut/walnut. Preliminary results of the application of anti-Cor a 14 IgY electrochemical immunosensor to incurred foods established a LOD of 1 mg kg−1 of hazelnut in wheat (0.16 mg kg−1 hazelnut protein).