Characterization of procaine metabolism as probe for the butyrylcholinesterase enzyme investigation by simultaneous determination of procaine and its metabolite using capillary electrophoresis with electrochemiluminescence detection

SERS and EC-SERS detection of local anesthetic procaine using Pd loaded highly reduced graphene oxide nanocomposite substrate

The localized surface plasmon resonance (LSPR) excitations are critical towards achieving sizable spectral enhancements of the Raman scattered light. Herein, the synthesis of palladium-based highly reduced graphene oxide (Pd-HRG) with LSPR properties as an effective surface-enhanced Raman scattering (SERS) substrate and its utility in the highly sensitive detection of procaine are reported. The concentration detection of procaine samples was optimized by applying a set of pre-concentration parameters. The Pd-HRG nanocomposite showed a remarkable LSPR response with a Raman enhancement factor of 8.7 × 10². The Pd-HRG is employed to modify fluorine doped tin oxide electrode (Pd-HRG/FTO), resulted with an enhancement factor of 7.5 × 10⁴ corresponding to the EC-SERS technique. The electronic and surface properties of synthesized Pd-HRG and functionalized FTO electrode were evaluated using Raman, infrared, EIS, XRD, FESEM and EDX techniques. Quantum chemical calculations were carried out to elaborate on the nature of interaction of procaine molecules with a nanostructured surface model. Pd-HRG, with an efficient and cost-effective fabrication, can be considered as a promising EC-SERS substrate for the detection of organic therapeutic drugs.

Diagnoses of Pathological States Based on Acetylcholinesterase and Butyrylcholinesterase

Two cholinesterases exist: Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). While AChE plays a crucial role in neurotransmissions, BChE has no specific function apart from the detoxification of some drugs and secondary metabolites from plants. Thus, both AChE and BChE can serve as biochemical markers of various pathologies. Poisoning by nerve agents like sarin, soman, tabun, VX, novichok and overdosing by drugs used in some neurodegenerative disorders like Alzheimer´s disease and myasthenia gravis, as well as poisoning by organophosphorus pesticides are relevant to this issue. But it appears that changes in these enzymes take place in other processes including oxidative stress, inflammation, some types of cancer and genetically conditioned diseases. In this review, the cholinesterases are introduced, the mechanism of inhibitors action is explained and the relations between the cholinesterases and pathologies are explained.

Copper, aluminum, iron and calcium inhibit human acetylcholinesterase in vitro

Acetylcholinesterase (AChE) is an important part of cholinergic nerves where it participates in termination of neurotransmission. AChE can be inhibited by e.g. some Alzheimer disease drugs, nerve agents, and secondary metabolites. In this work, metal salts aluminum chloride, calcium chloride, cupric chloride, ferric chloride, potassium chloride, magnesium chloride and sodium chloride were tested for their ability to inhibit AChE. Standard Ellman assay based on human recombinant AChE was done and inhibition was measured using Dixon plot. No inhibition was proved for sodium, potassium and magnesium ions. However, aluminum, cupric, ferric and calcium ions were able to inhibit AChE via noncompetitive mechanism of inhibition. Though the inhibition is much weaker when compared to e.g. drugs with noncompetitive mechanism of action, biological relevance of the findings can be anticipated.

Advances in capillary electrophoretic enzyme assays

In recent years, capillary electrophoresis (CE) has become a frequently used tool for enzyme assays due to its well-recognized advantages such as high separation efficiency, short analysis time, small sample and chemicals consumption. The published applications cover all aspects of enzyme characterization and analysis including the determination of the enzyme activity, substrate and modulator characterization and identification, as well as the investigation of enzyme-mediated metabolic pathways of bioactive molecules. The CE assays may be classified into two general categories: (1) pre-capillary assays where the reactions are performed offline followed by CE analysis of the substrates and products and (2) online assays when the enzyme reaction and separation of the analytes are performed in the same capillary. In online assays, the enzyme may be either immobilized or in solution. The latter is also referred to as electrophoretically mediated microanalysis (EMMA). The present review will highlight the literature of CE-based enzyme assays from 2006 to November 2009. One section will be devoted to applications of microfluidic devices.

Capillary electrophoresis with electrochemiluminescent detection for highly sensitive assay of genetically modified organisms

A capillary electrophoresis coupled with electrochemiluminescent detection system (CE-ECL) was developed for the detection of polymerase chain reaction (PCR) amplicons. The ECL luminophore, tris(1,10-phenanthroline) ruthenium(II) (Ru(phen)(3)(2+)), was labeled to the PCR primers before amplification. Ru(phen)(3)(2+) was then introduced to PCR amplicons by PCR amplification. Eventually, the PCR amplicons were separated and detected by the homemade CE-ECL system. The detection of a typical genetically modified organism (GMO), Roundup Ready Soy (RRS), was shown as an example to demonstrate the reliability of the proposed approach. Four pairs of primers were amplified by multiple PCR (MPCR) simultaneously, three of which were targeted on the specific sequence of exogenous genes of RRS, and another was targeted on the endogenous reference gene of soybean. Both the conditions for PCR amplification and CE-ECL separation and detection were investigated in detail. Results showed that, under the optimal conditions, the proposed method can accurately identifying RRS. The corresponding limit of detection (LOD) was below 0.01% with 35 PCR cycles.