Farid Oukacine

Joseph Fourier University | UJF · Département de Pharmacochimie Moléculaire

Poly(styrene-co-acrylic acid) (St/AA) and poly(styrene-co-methacrylic acid) (St/MA) nanolatexes with different acid contents were prepared by emulsion copolymerization and were analyzed by capillary electrophoresis (CE) and by laser doppler velocimetry (LDV). Due to the intrinsic differences in the methodologies, CE (separative technique) and LDV (...

An isotachophoretic method has been developed for mobilizing and focusing bacteria. This allows quantification and detection of bacteria in a narrow zone. Very good linearity was obtained for Micrococcus lysodeikticus (also called Micrococcus luteus, studied as a model of Gram+ bacteria) in the range of 0.4 × 10(8) cells/mL to 2.9 × 10(8) cells/mL,...

Herein, we studied the chiral resolution properties of a repertoire of arbitrarily chosen DNA oligonucleotides (ON). Ten oligonucleotidic sequences characterized by diverse base compositions, sizes and structural features, ranging from secondary structure-free homo-oligonucleotides to duplex, hairpin and three-way junction architectures, were inves...

Mesoporous Silica Nanoparticles (MSNs) have been increasingly investigated as versatile drug delivery carriers. A particular challenge for the systemic use of MSNs lies in the control of their degradation, which has not been fully understood until now. We implemented standard dynamic light scattering (DLS) experiments and introduced a novel DLS tec...

A new analytical methodology, using capillary electrophoresis in indirect UV absorbance mode, is developed for the quantification of analytes in the absence of reference materials. The methodology allows the quantification of organic molecules and/or small ions, anionic or cationic, absorbing or not in the UV range, carrying either one or two elect...

We introduced an aptamer switch design that relies on the ability of post‐transition/transition metal ions to trigger, through their coordination to nucleobases, substantial DNA destabilization. In the absence of molecular target, the addition of one such metal ion to usual aptamer working solutions promotes the formation of an alternative, inert D...

Structural transition metal ions: Post‐transition/transition metal ions can induce, through their coordination to nucleobases, substantial DNA destabilization. We exploited such property for elaborating fluorescent aptamer probes that switch between inert, metal ion‐complexed and active, target‐bound states. This very simple structural switching st...

Naturally occurring polymers (and their derivatives) such as polysaccharides and proteins are very popular chiral selectors in analytical sciences. In contrast, nucleic acids have received much less attention in the enantiomeric analysis field. However, some significant advances have been accomplished during the last thirty years. The present revie...

Titration methods are routinely used in the laboratories for the quantification of acids and bases, for the complexometric determination of metal ions and for the ion-pair titrations of drugs in pharmaceutical control. They also find application in a wide variety of chemical and biochemical studies. However, conventional titration methods (CTM) req...

The inline coupling of the field-amplified sample injection (FASI) to Taylor dispersion analysis (TDA) was used to characterize low-UV absorbing carboxylated silica nanoparticles (cNPs). The hydrodynamic diameters (Dh) were measured by using a commercial capillary electrophoresis instrument. The proposed methodology did not require any complicated...

We recently reported that a great variety of DNA oligonucleotides (ONs) used as chiral selectors in partial-filling capillary electrophoresis (CE) exhibited interesting enantioresolution properties towards low-affinity DNA binders. Herein, the sequence prerequisites of ONs for the CE enantioseparation process were studied. First, the chiral resolut...

A novel electrokinetic preconcentration technique based on multiple isotachophoresis (M-ITP) realised in a micro-bored capillary to improve sensitivity for capillary electrophoresis with hydrodynamic injection was developed. The M-ITP operation relies on pressure-assisted pushing of a preconcentrated sample plug after the first ITP process back to...

In this communication, we present a very simple strategy to focus covalently derivatized proteins for high sensitivity CE analysis by LIF detection. We demonstrated that the covalently tagged protein can be focused just by adding SDS at a concentration above the CMC in the derivatized sample. Under specific injection conditions, SDS concentration b...

We report an improved capillary electrophoresis method to monitor in vitro the self-assembly of monomeric amyloid β-peptide (Aβ1–42) and in particular the crucial early steps involved in the formation of the neurotoxic oligomers. In order to start the kinetics from the beginning, sample preparation was optimized to provide samples containing exclus...

(1,2-diamino-cyclohexane)platinum(II) ((DACH)Pt) loaded polymeric micelles of poly(ethylene glycol-b-sodium glutamate) (PEG-b-PGlu) are currently studied as a potential candidate to replace oxaliplatin in the treatment of cancers with the aim to reduce side effects like cumulative peripheral distal neurotoxicity and acute dysesthesias. As for all s...

Silver nanoparticles possess potent antibacterial properties and have extremely high affinities to radioiodine. For several applications, it is essential to anchor the nanoparticles to microparticles or solid surfaces to make them insoluble while retaining their unique properties. This current work is related to the design of anionic and cationic m...

This manuscript describes a new analytical methodology that allows one to stop the apparent fluid flow in uncoated fused silica capillaries. This method, which requires neither capillary coating nor buffer additive, is based on the use of a 22% polyethylene oxide gel which is placed at the anodic end of the capillary. Its high viscosity precludes i...

Electrophoretically mediated microanalysis was implemented for on-line fluorescence derivatization of ubiquitin, a potential biomarker of Alzheimer disease. Ubiquitin was labeled on its amino groups by the Fluoprobes® 488 N-hydroxysuccinimide. The pH of the background electrolyte, the applied electric field and the washing process of the capillary...

Click chemistry by copper-mediated azide/alkyne cycloaddition reaction is known as a very efficient synthetic pathway for chemical coupling and for surface functionalization. The attractiveness of this reaction is due to the selectivity of the reaction of azides and alkynes. Nevertheless, the control of the kinetics of the reaction and the characte...

The isotachophoretic analysis of different bacterial strains was studied using capillaries with different internal diameters from 50 to 250μm. Several injection modes were investigated and compared in order to improve the limit of detection of bacteria by capillary isotachophoresis. A system suitability test obtained from the separation voltage was...

A new methodology for an antibacterial assay based on capillary electrophoresis with multiple UV detection points has been proposed. The possible antibacterial activity of cationic molecules on bacteria (Gram-positive and Gram-negative) is studied by detecting the bacteria before, during, and after their meeting with the cationic antibacterial comp...

This work describes a simple technical modification for doing Taylor dispersion analysis with two UV detection points on a commercial capillary electrophoresis apparatus. So far, double UV detection was only possible using specific detectors that are external to the capillary electrophoresis apparatus. In this work, the detection interface of the c...

A repeatable preconcentration electrophoretic methodology for the analysis of bacteria was developed. This method is based on an isotachophoretic mode coupled with a simultaneous hydrodynamic-electrokinetic injection in conditions of field-amplified sample injection. This electrophoretic method allows the quantification of Enterobacter cloacae (stu...

The study of interactions between oppositely multicharged (macro)molecules remains a challenging issue. In frontal analysis capillary electrophoresis (FACE), it is difficult to avoid the adsorption of one of the interacting partners onto the capillary wall. In this work, we demonstrate the possibility to use FACE and affinity capillary electrophore...