RESUMEN
A new approach for preparation of active plasmonic component with capability to switch on/off localized surface plasmon resonance (LSPR) by piezoelectric effect is described. Polyvinylidene fluoride (PVDF) was patterned by polarized KrF excimer laser beam. The polarization was perpendicular to polymer orientation introduced during the poling procedure. Consequently the silver nanoclusters were sputtered onto the polymer surface. Application of an external electric field leads to polymer stretching and surface smoothening. Simultaneously, silver clusters are elongated and interconnected; this process leads to dramatic decrease of surface resistance and complete quenching of plasmon related absorption.
RESUMEN
Materials prepared on the base of bioactive silver compounds have become more and more popular due to low microbial resistance to silver. In the present work, the efficiency of polymethylmethacrylate (PMMA) thin films doped with silver ions, nanoparticles and silver-imidazole polymer complex was studied by a combination of AAS, XPS and AFM techniques. The biological activities of the proposed materials were discussed in view of the rate of silver releasing from the polymer matrix. Concentrations of Ag active form were estimated by its ability to interact with l-cysteine using electronic circular dichroism spectroscopy. Rates of the released silver were compared with the biological activity in dependence on the form of embedded silver. Antimicrobial properties of doped polymer films were studied using two bacterial strains: Staphylococcus epidermidis and Escherichia coli. It was found that PMMA films doped with Ag(+) had greater activity than those doped with nanoparticles and silver-imidazole polymeric complexes. However, the antimicrobial efficiency of Ag(+) doped films was only short-term. Contrary, the antimicrobial activity of silver-imidazole/PMMA films increased in time of sample soaking.
Asunto(s)
Antibacterianos/química , Antibacterianos/farmacología , Nanopartículas/química , Polimetil Metacrilato/química , Polimetil Metacrilato/farmacología , Plata/química , Plata/farmacología , Cisteína/metabolismo , Escherichia coli/efectos de los fármacos , Imidazoles/química , Imidazoles/farmacología , Iones/química , Pruebas de Sensibilidad Microbiana/métodos , Polímeros/química , Compuestos de Plata/química , Compuestos de Plata/farmacología , Staphylococcus epidermidis/efectos de los fármacosRESUMEN
A 62-year-old man with a history of chronic alcohol abuse presented with severe pancreatic panniculitis associated with an acute exacerbation of chronic pancreatitis.