Molecularly imprinted graphite spray ionization-ion mobility spectrometry: application to trace analysis of the pesticide propoxur.

A porous graphite sheet modified by a molecularly imprinted polymer (MIP) was directly used as the spray ionization source for ion mobility spectrometry (IMS). Therefore, it was possible to selectively analyze samples extracted by the molecularly imprinted polymer. This obviates the need for the steps of elution, solvent evaporation, dissolution and injection.

DNA G-quadruplexes binding and antitumor activity of palladium aryl oxime ligand complexes encapsulated in either albumin or algal cellulose nanoparticles.

The interactions between two Pd complexes, designated as [Pd(C,N-(CHC(Cl) = NO)-4)] (complex 1) and [Pd(CHC = NO)] (complex 2), with the human telomeric G-quadruplex DNA, 5'-G(TAG)-3' (HTG21), were monitored using spectroscopic, biological, and molecular modeling studies. According to the UV-vis results, these complexes can strongly induce and stabilize G-quadruplex DNA structure with K = 4.5(±0.

Porous graphite sheet spray ionization ion mobility spectrometry.

In this work, a porous graphite sheet is introduced as the substrate in a spray ionization source for ion mobility spectrometry (PGSI-IMS) for the first time. This ionization source has some important advantages in comparison with the hollow needle, which is conventionally used in electrospray ionization. In order to prepare the hydrophilic surface needed to load samples on a graphite substrate, the graphite sheet was treated with hot sulfuric acid solution for 2 hours.

Ingenious pH-sensitive etoposide loaded folic acid decorated mesoporous silica-carbon dot with carboxymethyl-βcyclodextrin gatekeeper for targeted drug delivery and imaging.

A new strategy is reported for the synthesis of label-free fluorescent mesoporous silica (MS) by the introduction of fluorescent carbon dots in the MSs (MSCDs) in this work. Etoposide (ETO) loaded MSCDs have been used as a drug model. Carboxymethyl β-cyclodextrin (CβCD) used as a gatekeeper agent was attached to amine-functionalized MSCDs to retain ETO molecules inside the nanocarrier.

Aptamer-modified carbon nanomaterial based sorption coupled to paper spray ion mobility spectrometry for highly sensitive and selective determination of methamphetamine.

A cellulose paper was modified with an aptamer against methamphetamine on either carbon dots (CDs) or on multichannel carbon nanotubes (CNTs). The resulting sorbent was applied to the extraction of METH from blood or saliva. The METH-loaded paper than also was directly applied as a paper spray ionization source in ion mobility spectrometry.

A fluorescent aptasensor for analysis of adenosine triphosphate based on aptamer-magnetic nanoparticles and its single-stranded complementary DNA labeled carbon dots.

A new fluorimetric aptasensor was designed for the determination of adenosine triphosphate (ATP) based on magnetic nanoparticles (MNPs) and carbon dots (CDs). In this analytical strategy, an ATP aptamer was conjugated on MNPs and a complementary strand of the aptamer (CS) was labeled with CDs. The aptamer and its CS were hybridized to form a double helical structure.

Conical Torch: The Next-Generation Inductively Coupled Plasma Source for Spectrochemical Analysis.

A completely new ICP torch for optical/mass spectrometry is introduced with a conical geometry leading to significant reduction in gas and power consumption. As a new holistic methodology, the torch has been designed on the basis of fluid flow patterns, heat transfer, plasma physics, and analytical performance. Computer simulations, capable of accounting for magneto-hydrodynamic effects, have been used to optimize torch geometry.

Folate receptor-targeted multimodal fluorescence mesosilica nanoparticles for imaging, delivery palladium complex and in vitro G-quadruplex DNA interaction.

New folic acid-conjugated mesoporous silica nanoparticles were synthesized. The effect of calcination at 400°C on the fluorescence characteristics of mesoporous silica nanoparticles were studied in this work. The formed carbon dots (CDs) from calcination were used as the source of fluorescence.

Immobilized aptamer paper spray ionization source for ion mobility spectrometry.

A selective thin-film microextraction based on aptamer immobilized on cellulose paper was used as a paper spray ionization source for ion mobility spectrometry (PSI-IMS), for the first time. In this method, the paper is not only used as an ionization source but also it is utilized for the selective extraction of analyte, based on immobilized aptamer. This combination integrates both sample preparation and analyte ionization in a Whatman paper.

Aptasensor based on fluorescence resonance energy transfer for the analysis of adenosine in urine samples of lung cancer patients.

A new aptasensor was designed for the analysis of adenosine based on fluorescence resonance energy transfer (FRET) between CdS quantum dot (QDs) as a donor and polypyrrole (Ppy) as an acceptor. The QDs were covalently bonded to anti-adenosine aptamer where its fluorescence was quenched by Ppy. When Ppy was replaced by adenosine, the fluorescence of QDs was restored and its intensity was proportional to the adenosine concentration.

Aptamer-conjugated magnetic nanoparticles for extraction of adenosine from urine followed by electrospray ion mobility spectrometry.

Magnetic nanoparticles (MNPs) conjugated with aptamer was developed for the selective extraction of adenosine in urine samples followed by electrospray ionization-ion mobility spectrometry (ESI-IMS). The ion mobility spectrum of adenosine showed two peaks at low concentrations and two more peaks related to dimer of adenosine at high concentrations. However, the ion mobility spectrum of eluent at low concentration showed only the peaks related to dimer of adenosine.

Spectroscopic, biological, and molecular modeling studies on the interactions of [Fe(III)-meloxicam] with G-quadruplex DNA and investigation of its release from bovine serum albumin (BSA) nanoparticles.

The guanine-rich sequence, specifically in DNA, telomeric DNA, is a potential target of anticancer drugs. In this work, a mononuclear Fe(III) complex containing two meloxicam ligands was synthesized as a G-quadruplex stabilizer. The interaction between the Fe(III) complex and G-quadruplex with sequence of 5'-G3(T2AG3)3-3' (HTG21) was investigated using spectroscopic methods, molecular modeling, and polymerase chain reaction (PCR) assays.

Anticodeine aptamer immobilized on a Whatman cellulose paper for thin-film microextraction of codeine from urine followed by electrospray ionization ion mobility spectrometry.

A combination of thin-film microextaction based on an aptamer immobilized on modified Whatman cellulose paper followed by electrospray ionization ion mobility spectrometry has been developed for the analysis of codeine in urine samples. The immobilization is based on the covalent linking of an amino-modified anticodeine aptamer to aldehyde groups of the oxidized cellulose paper. The covalent bonds were examined by infrared spectroscopy and elemental analysis.

A mononuclear zinc(II) complex with piroxicam: crystal structure, DNA- and BSA-binding studies; in vitro cell cytotoxicity and molecular modeling of oxicam complexes.

A new mononuclear Zn(II) complex, trans-[Zn(Pir)2(DMSO)2], where Pir(-) is 4-hydroxy-2-methyl-N-2-pyridyl-2H-1,2-benzothiazine-3-carboxamide-1,1-dioxide (piroxicam), has been synthesized and characterized. The crystal structure of the complex was obtained by the single crystal X-ray diffraction technique. The interaction of the complex with DNA and BSA was investigated.

Extraction of methocarbamol from human plasma with a polypyrrole/multiwalled carbon nanotubes composite decorated with magnetic nanoparticles as an adsorbent followed by electrospray ionization ion mobility spectrometry detection.

In this work, a polypyrrole/multiwalled carbon nanotubes composite decorated with Fe3 O4 nanoparticles was chemically synthesized and applied as a novel adsorbent for the extraction of methocarbamol from human plasma. Electrospray ionization ion mobility spectrometry was used for the determination of the analyte. The properties of the magnetic-modified adsorbent were characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform IR spectroscopy, and X-ray diffraction.

Experimental and molecular modeling studies of the interaction of the polypyridyl Fe(II) and Fe(III) complexes with DNA and BSA.

Two mononuclear iron complexes, [Fe(tppz)₂](PF₆)₂·H₂O (1) and Fe(tppz)Cl₃·2CHCl₃ (2) where tppz is (2,3,5,6-tetra(2-pyridyl)pyrazine), have been synthesized and characterized by elemental analysis, spectroscopic methods (UV-Vis and IR) and single crystal X-ray structure analysis. The interaction of (1) as the nitrate salt ([Fe(tppz)₂](NO₃)₂) with calf-thymus DNA (CT-DNA) has been monitored by UV-Vis spectroscopy, competitive fluorescence titration, circular dichroism (CD), voltammetric techniques, viscosity measurement, and gel electrophoresis. Gel electrophoresis of DNA with [Fe(tppz)₂](NO₃)₂ demonstrated that the complex also has the ability to cleave supercoiled plasmid DNA.

Experimental and molecular modeling studies on the interaction of the Ru(II)-piroxicam with DNA and BSA.

A mononuclear Ru(II) complex containing two piroxicam (Pir(-)) ligands was synthesized and fully characterized. Interaction studies of the Pir(-) anion and the Ru(II) complex with DNA and BSA were carried out using spectroscopic techniques. The results suggested that the Pir(-) anion binds to DNA in a moderately strong fashion via intercalation between the base stacks of double-stranded DNA, while the Ru(II) complex is a groove binder and interacts with DNA with more affinity.

Aptamer based extraction followed by electrospray ionization-ion mobility spectrometry for analysis of tetracycline in biological fluids.

An extraction method based on aptamer sorbent followed by electrospray ionization-ion mobility spectrometry (ESI-IMS) has been developed for the analysis of tetracycline in human urine and plasma samples. The effect of extraction parameters on the extraction efficiency including washing (solvent type and volume) and elution (solvent type, volume and flow rate) were investigated. Under the optimized conditions, the linear dynamic ranges for tetracycline in urine and plasma samples were found to be 0.

A chemiluminescent metalloimmunoassay based on copper-enhanced gold nanoparticles for quantification of human growth hormone.

A chemiluminescence (CL) immunoassay was developed to determine human growth hormone (hGH) based on copper-enhanced gold nanoparticles. In this method, gold nanoparticles were deposited on polystyrene wells for adsorption of human growth antibodies as well as catalyst for reducing of copper ions from the copper enhancer solution. The reduction of copper ions was prevented where the gold nanoparticles were covered by the antibody-antigen immunocomplex.

Investigation of the interaction between amodiaquine and human serum albumin by fluorescence spectroscopy and molecular modeling.

The interaction of amodiaquine (AQ) with human serum albumin (HSA) has been studied by fluorescence spectroscopy. Based on the sign and magnitude of the enthalpy and entropy changes (ΔH(0) = -43.27 kJ mol(-1) and ΔS(0) = -50.

Combined fluorescence spectroscopy and molecular modeling studies on the interaction between harmalol and human serum albumin.

The interaction between harmalol and human serum albumin (HSA) has been studied by fluorescence spectroscopy and molecular modeling methods. The intrinsic fluorescence of HSA was quenched by harmalol, which was rationalized in terms of the static quenching mechanism. The binding parameters, quenching constants and conformation changes were determined by fluorescence quenching method.

Combination of corona discharge ion mobility spectrometry with a novel reagent gas and two immiscible organic solvent liquid-liquid-liquid microextraction for analysis of clomipramine in biological samples.

A novel and sensitive method based on combination of two immiscible organic solvents hollow fiber-based liquid-liquid-liquid microextraction and corona discharge ion mobility spectrometry (HF-LLLME-CD-IMS) was employed for the analysis of clomipramine in human urine and plasma. The effect of formic, acetic and propionic acid as the reagent gas (dopant) on the corona discharge ion mobility signal was investigated. The influence of dopant amount was also studied.

Analysis of amantadine in biological fluids using hollow fiber-based liquid-liquid-liquid microextraction followed by corona discharge ion mobility spectrometry.

A method based on liquid-liquid-liquid microextraction combined with corona discharge ion mobility spectrometry was developed for the analysis of amantadine in human urine and plasma samples. Amantadine was extracted from alkaline aqueous sample as donor phase through a thin phase of organic solvent (n-dodecane) filling the pores of the hollow fiber wall and then back extracted into the organic acceptor phase (methanol) located in the lumen of the hollow fiber. All variables affecting the extraction of analyte including acceptor organic solvent type, concentration of NaOH in donor phase, ionic strength of the sample and extraction time were studied.

A structure-based QSAR and docking study on imidazo[1,5-a][1,2,4]-triazolo[1,5-d][1,4,]benzodiazepines as Selective GABA(A) α5 inverse agonists.

As three-dimensional (3D) structure of the GABA(A) α5 was not determined, the crystal structure of 2Vl0E at 3.3 Å resolution which is a ligand-gated K(+) channel was used as a template in homology modeling, and the result was used in molecular dynamic simulation for obtaining its conformation in a water sphere. The resulted conformation of the receptor was used for docking with the most potent of imidazo[1,5-a][1,2,4]-triazolo[1,5-d][1,4,] benzodiazepines drugs to find out binding sites and consequently the types of the interaction between the drugs and receptor.

Analysis of testosterone in human urine using molecularly imprinted solid-phase extraction and corona discharge ion mobility spectrometry.

Analysis of testosterone was accomplished using corona discharge ion mobility spectrometry. Molecular imprinted polymer was used for the extraction and pre-concentration of testosterone. Analytical parameters including precision, dynamic range and detection limit were obtained.