Search results for "Imprinting"
showing 10 items of 124 documents
Imbibition of Femtoliter-Scale DNA-Rich Aqueous Droplets into Porous Nylon Substrates by Molecular Printing
2019
This work presents the first reported imbibition mechanism of femtoliter (fL)-scale droplets produced by microchannel cantilever spotting (μCS) of DNA molecular inks into porous substrates (hydrophilic nylon). Differently from macroscopic or picoliter droplets, the downscaling to the fL-size leads to an imbibition process controlled by the subtle interplay of evaporation, spreading, viscosity, and capillarity, with gravitational forces being quasi-negligible. In particular, the minimization of droplet evaporation, surface tension, and viscosity allows for a reproducible droplet imbibition process. The dwell time on the nylon surface permits further tuning of the droplet lateral size, in acc…
Magnetic molecularly imprinted polymer for the simultaneous selective extraction of phenoxy acid herbicides from environmental water samples
2022
[EN] A selective magnetic molecularly imprinted polymer (MMIP) was synthetized with 4-chloro-2-methylphenoxyacetic acid as template and 4-vinylpiridine as monomer in presence of vinylized magnetite nanoparticles. Scanning electron microscopy, nitrogen adsorption-desorption isotherms, Fourier transform infrared spectrometry and vibrating sample magnetometry were applied to characterize the resulting material. The synthesized MMIP was applied as sorbent in magnetic molecularly imprinted solid-phase extraction (MMISPE) for selective extraction of a mixture of the five herbicides 4-chloro-2-methylphenoxyacetic acid (MCPA), 4-(4-chloro-2-methylphenoxy)butyric acid (MCPB), mecoprop (MCPP), fenoxa…
Biomolecular conjugation inside synthetic polymer nanopores via glycoprotein-lectin interactions
2011
We demonstrate the supramolecular bioconjugation of concanavalin A (Con A) protein with glycoenzyme horseradish peroxidase (HRP) inside single nanopores, fabricated in heavy ion tracked polymer membranes. Firstly, the HRP-enzyme was covalently immobilized on the inner wall of the pores using carbodiimide coupling chemistry. The immobilized HRP-enzyme molecules bear sugar (mannose) groups available for the binding of Con A protein. Secondly, the bioconjugation of Con A on the pore wall was achieved through its biospecific interactions with the mannose residues of the HRP enzyme. The immobilization of biomolecules inside the nanopore leads to the reduction of the available area for ionic tran…
Analysis of Nicotine and Its Oxidation Products in Nicotine Chewing Gum by a Molecularly Imprinted Solid-Phase Extraction
2000
Chromatographic stationary phases showing exceptional selectivity for nicotine can be prepared by the technique of molecular imprinting. Such phases were used in the search for a rapid cleanup step for nicotine and some of its oxidation products in chewing gum formulations. Thus, using an organic mobile phase, the nicotine analytes from chewing gums dissolved in nonpolar solvent were retained, whereas the nonpolar matrix eluted close to the void peak. A subsequent switch to an acidic mobile phase resulted in elution of the analytes as one sharp peak. Due to weak binding of the less basic oxidation products, other imprinted polymers were tested, and the solid-phase extraction procedure was o…
Genome-wide parent-of-origin DNA methylation analysis reveals the intricacies of human imprinting and suggests a germline methylation-independent mec…
2014
Genomic imprinting is a form of epigenetic regulation that results in the expression of either the maternally or paternally inherited allele of a subset of genes (Ramowitz and Bartolomei 2011). This imprinted expression of transcripts is crucial for normal mammalian development. In humans, loss-of-imprinting of specific loci results in a number of diseases exemplified by the reciprocal growth phenotypes of the Beckwith-Wiedemann and Silver-Russell syndromes, and the behavioral disorders Angelman and Prader-Willi syndromes (Kagami et al. 2008; Buiting 2010; Choufani et al. 2010; Eggermann 2010; Kelsey 2010; Mackay and Temple 2010). In addition, aberrant imprinting also contributes to multige…
The placenta: phenotypic and epigenetic modifications induced by Assisted Reproductive Technologies throughout pregnancy
2015
International audience; Today, there is growing interest in the potential epigenetic risk related to assisted reproductive technologies (ART). Much evidence in the literature supports the hypothesis that adverse pregnancy outcomes linked to ART are associated with abnormal trophoblastic invasion. The aim of this review is to investigate the relationship between epigenetic dysregulation caused by ART and subsequent placental response. The dialogue between the endometrium and the embryo is a crucial step to achieve successful trophoblastic invasion, thus ensuring a non-complicated pregnancy and healthy offspring. However, as described in this review, ART could impair both actors involved in t…
Surface molecularly imprinted silica for selective solid-phase extraction of biochanin A, daidzein and genistein from urine samples
2015
Selective molecularly imprinted silica polymer (SiO2MIP) for extraction of biochanin A, daidzein and genistein was synthesized using the surface molecular imprinting technique with the silica gel as a support. Biochanin A (BCA) was used as a template, 3-aminopropyltriethoxysilane (APTES) as a functional monomer, and tetraethoxysilicane (TEOS) as a cross-linker. Non-imprinted polymer with the sol–gel process (SiO2NIP) was also prepared for comparison. The synthesized polymers were characterized by Fourier transform infrared spectrometry (FTIR), scanning electron microscopy (SEM) and a standard Brunauer-Emett-Teller (BET) and Barret–Joyner–Halenda (BJH) analysis. The obtained results indicate…
The application of the supported liquid membrane and molecularly imprinted polymers as solid acceptor phase for selective extraction of biochanin A f…
2018
An efficient sample clean-up and preconcentration procedure for phytoestrogens analysis in urine has been developed. It was based on a combination of solid phase extraction with hollow-fiber supported liquid membrane and molecularly imprinted beads (MIPs-HF-SLM-SPE). The molecularly imprinted polymers (MIPs) were synthesized by precipitation polymerization technique with biochanin A (BCA) as a template, giving narrowly dispersed microspheres with a regular shape. As the functional monomer, (dimethylamino)ethyl methacrylate (-DEM) turned out to be better than methacrylic acid (MAA) to get the best-imprinted effects. The MIPs used as sorbents in the MIPs-HF-SLM-SPE extraction process exhibite…
Pressure-Induced Binding Sites in Molecularly Imprinted Network Polymers
1997
Molecular imprinting in network polymers under high pressure was studied as a means of inducing selective binding sites for molecular recognition. Network polymers of methacrylic acid and ethylene ...
Germline correction of an epimutation related to Silver-Russell syndrome.
2015
Like genetic mutations, DNA methylation anomalies or epimutations can disrupt gene expression and lead to human diseases. However, unlike genetic mutations, epimutations can in theory be reverted through developmental epigenetic reprograming, which should limit their transmission across generations. Following the request for a parental project of a patient diagnosed with Silver-Russell syndrome (SRS), and the availability of both somatic and spermatozoa DNA from the proband and his father, we had the exceptional opportunity to evaluate the question of inheritance of an epimutation. We provide here for the first time evidence for efficient reversion of a constitutive epimutation in the sperm…