Fabrication of an oxytetracycline molecular-imprinted sensor based on the competition reaction via a GOD-enzymatic amplifier

A molecularly imprinted sensor for single-molecule detection of pesticide metabolite at the amol/L level sensitized by water-soluble luminol derivative encapsulated liposome via click reaction

A novel luminol derivative, 4-[(1,4-dioxo-1,2,3,4-tetrahydrophthalazin-5-yl)amino]-4-oxobut-2-enoic acid (ALD) with electrochemiluminescence intensity and stability characteristics similar to luminol, but higher solubility in near neutral solution, was designed and synthesized in this study. Using this derivative, a molecular imprinted electrochemiluminescence sensor (MIECLS) was prepared for the sensitive and selective determination of 2-amino-5-mercapto-1,3,4-thiadiazole (AMT), a metabolite of bismerthiazol, thiediazole copper, thiazole zinc, and other pesticides. The ALD probes encapsulated in liposomes are immobilized on the molecularly imprinted film by light-triggered click reaction, and the concurrent release of multiple probes allows for highly sensitive detection. In the AMT concentration range of 1.00 × 10-18 - 5.00 × 10-13 mol/L, the relation between ECL response and log AMT concentration is linear. With a detection limit of 5.25 × 10-19 mol/L (about 4 - 6 molecules in 10 μL of the sample), the sensor allows for high sensitivity analysis of ultra-trace amounts of small organic compounds. In general, the ECL-based single-molecule detection technique proposed herein might be a promising alternative to fluorescence single-molecule detection.

Extremely Sensitive Molecularly Imprinted ECL Sensor with Multiple Probes Released from Liposomes Immobilized by a Light-Triggered Click Reaction

A molecularly imprinted electrochemiluminescence sensor was prepared for sensitive and selective determination of aminotriazole via a novel strategy of multiple Ru(bpy)₃Cl₂ probes released from liposomes immobilized by a light-triggered click reaction. This sensing strategy provides a platform for trace detection of amino-containing pesticides. The target on the molecularly imprinted membrane connected to the Ru(bpy)₃Cl₂-encapsulated liposomes via the click reaction. After the destabilizing agent Triton X-100 was added, numerous Ru(bpy)₃Cl₂ molecules were released by liposomes on the molecularly imprinted polymer electrode. The ECL response of the sensor was linearly proportional to the logarithm of the aminotriazole concentration ranging from 5.00 × 10^-18 to 1.00 × 10^-12 mol/L, and the detection limit was 1.15 × 10^-18 mol/L. The sensitivity of the detection was significantly improved, and the analysis process was simplified.

A carbon dot-based fluorometric probe for oxytetracycline detection utilizing a Förster resonance energy transfer mechanism

A carbon dot (CD)-based fluorometric probe for oxytetracycline (OTC) detection utilizing a Förster resonance energy transfer (FRET) mechanism was firstly developed. Upon addition of OTC, the blue fluorescence of the CDs peaked at 405 nm was quickly quenched, with a new fluorescence peaked at 505 nm attributed to OTC was observed within 30 s. A visual fluorescent color change of the CDs solution from blue to green was discerned under a 365 nm UV light irradiation. The CDs displayed a high sensitivity and selectivity toward OTC with a low detection limit of 0.41 μM. Furthermore, the probe was applied to detect OTC in water, milk, and pork samples with a satisfied recovery.

How Reliable Is the Electrochemical Readout of MIP Sensors?

Electrochemical methods offer the simple characterization of the synthesis of molecularly imprinted polymers (MIPs) and the readouts of target binding. The binding of electroinactive analytes can be detected indirectly by their modulating effect on the diffusional permeability of a redox marker through thin MIP films. However, this process generates an overall signal, which may include nonspecific interactions with the nonimprinted surface and adsorption at the electrode surface in addition to (specific) binding to the cavities. Redox-active low-molecular-weight targets and metalloproteins enable a more specific direct quantification of their binding to MIPs by measuring the faradaic current. The in situ characterization of enzymes, MIP-based mimics of redox enzymes or enzyme-labeled targets, is based on the indication of an electroactive product. This approach allows the determination of both the activity of the bio(mimetic) catalyst and of the substrate concentration.

An electrochemical impedimetric sensor based on biomimetic electrospun nanofibers for formaldehyde

Herein, simple molecular recognition sites for formaldehyde were designed on electrospun polymer nanofibers.

Molecular imprinting science and technology: a survey of the literature for the years 2004-2011

Herein, we present a survey of the literature covering the development of molecular imprinting science and technology over the years 2004-2011. In total, 3779 references to the original papers, reviews, edited volumes and monographs from this period are included, along with recently identified uncited materials from prior to 2004, which were omitted in the first instalment of this series covering the years 1930-2003. In the presentation of the assembled references, a section presenting reviews and monographs covering the area is followed by sections describing fundamental aspects of molecular imprinting including the development of novel polymer formats. Thereafter, literature describing efforts to apply these polymeric materials to a range of application areas is presented. Current trends and areas of rapid development are discussed.

A molecularly imprinted electrochemical enzymeless sensor based on functionalized gold nanoparticle decorated carbon nanotubes for methyl-parathion detection

Schematic of MP MIP sensor and the possible mechanism.

Construction of a novel macroporous imprinted biosensor based on quartz crystal microbalance for ribonuclease A detection

A novel quartz crystal microbalance (QCM) biosensor with high selectivity and sensitivity has been developed for ribonuclease A determination. Macroporous protein imprinted films have been fabricated on the surface of QCM electrode using 2,2,3,4,4,4-hexafluorobutyl methacrylate (HFBMA) as the main matrix monomer, N-methacryloyl-histidine (MAH) as the functional monomer, and trimethylolpropane trimethacrylate (TRIM) as the cross-linker. The imprinted special surface area and the quantity of the imprinted sites were increased by the formation of macropores that were generated by employing calcium carbonate nanoparticles as the porogen. The selectivity factor was improved obviously for the fluoromonomer containing system, especially in dilute protein solution, which gets benefit from the reducing of the nonspecific adsorption of proteins. Furthermore, MAH can not only play the role as the functional monomer, but also improve the hydrophilicity of surface of the imprinted film, which makes for the adsorption of proteins. At last, the rigid skeleton structure made the films durable in the recycled tests.

Electrochemically synthesized polymers in molecular imprinting for chemical sensing

This critical review describes a class of polymers prepared by electrochemical polymerization that employs the concept of molecular imprinting for chemical sensing. The principal focus is on both conducting and nonconducting polymers prepared by electropolymerization of electroactive functional monomers, such as pristine and derivatized pyrrole, aminophenylboronic acid, thiophene, porphyrin, aniline, phenylenediamine, phenol, and thiophenol. A critical evaluation of the literature on electrosynthesized molecularly imprinted polymers (MIPs) applied as recognition elements of chemical sensors is presented. The aim of this review is to highlight recent achievements in analytical applications of these MIPs, including present strategies of determination of different analytes as well as identification and solutions for problems encountered.