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2.
Lab Chip ; 15(21): 4227-31, 2015 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-26371689

RESUMO

We demonstrate thiol-acrylate microfluidics prepared via soft lithography for single-step protein immobilization and fluorescence-based pathogen detection. Such microfluidics are formed via room temperature curing, and bonded without oxygen plasma. The background fluorescence of the resin was found to be similar to PDMS for several filter sets. We also show that thiol-acrylate devices are able to bond to gold-coated surfaces, which allows for integration with microfabricated sensors.


Assuntos
Resinas Acrílicas/química , Escherichia coli O157/isolamento & purificação , Técnicas Analíticas Microfluídicas/métodos , Compostos de Sulfidrila/química , Anticorpos Imobilizados/química , Técnicas Biossensoriais , Dimetilpolisiloxanos/química , Espectrometria de Fluorescência
3.
J Mater Chem B ; 2(43): 7495-7501, 2014 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-32261888

RESUMO

This work takes advantage of the transformation of lidocaine hydrochloride into deep-eutectic solvents (DESs) - ionic liquid analogues - to incorporate polymerizable counterparts into DESs, such that polymer-drug complexes are synthesized by free-radical frontal polymerization without the use of a solvent. DESs are formed through hydrogen bonding of an ammonium salt with a hydrogen-bond donor (HBD). It is demonstrated that lidocaine hydrochloride - as the ammonium salt - is able to form DESs with acrylic acid and methacrylic acid. The properties of DESs allow frontal polymerization in the bulk with full conversion achieved in a one-pot synthesis, yielding monoliths of polymers loaded with a high concentration of drug. In in vitro experiments, the sustained release of the drug takes place in a controlled manner triggered by the pH, ionic strength and solubility of the drug in the medium. Such control is owed to the swelling of polymers as well as to the specific interactions between the drug and the polymers already established in the DES precursor. Finally, it is noteworthy that different monomers (such as HBD) and crosslinkers can be used, thus expanding the possibilities of drug delivery systems for transdermal technologies by exploiting the DES chemistry.

4.
Chaos ; 10(1): 224-230, 2000 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-12779377

RESUMO

This paper is devoted to the investigation of polymerization fronts converting a liquid monomer into a liquid polymer. We assume that the monomer and the polymer are immiscible and study the influence of the interfacial tension on the front stability. The mathematical model consists of the reaction-diffusion equations coupled with the Navier-Stokes equations through the convection terms. The jump conditions at the interface take into account the interfacial tension. Simple physical arguments show that the same temperature distribution could not lead to Marangoni instability for a nonreacting system. We fulfill a linear stability analysis and show that interaction of the chemical reaction and of the interfacial tension can lead to an instability that has another mechanism: the heat produced by the reaction decreases the interfacial tension and initiates the liquid motion. It brings more monomer to the reaction zone and increases even more the heat production. This feedback mechanism can lead to the instability if the frontal Marangoni number exceeds a critical value. (c) 2000 American Institute of Physics.

5.
Ann N Y Acad Sci ; 879: 194-214, 1999 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-10415828

Assuntos
Polímeros
6.
Chaos ; 8(2): 520-529, 1998 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12779755

RESUMO

This work is devoted to the investigation of propagating polymerization fronts converting a liquid monomer into a liquid polymer. We consider a simplified mathematical model which consists of the heat equation and equation for the depth of conversion for one-step chemical reaction and of the Navier-Stokes equations under the Boussinesq approximation. We fulfill the linear stability analysis of the stationary propagating front and find conditions of convective and thermal instabilities. We show that convection can occur not only for ascending fronts but also for descending fronts. Though in the latter case the exothermic chemical reaction heats the cold monomer from above, the instability appears and can be explained by the interaction of chemical reaction with hydrodynamics. Hydrodynamics changes also conditions of the thermal instability. The front propagating upwards becomes less stable than without convection, the front propagating downwards more stable. The theoretical results are compared with experiments. The experimentally measured stability boundary for polymerization of benzyl acrylate in dimethyl formamide is well approximated by the theoretical stability boundary. (c) 1998 American Institute of Physics.

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