RESUMEN

At a time of growing epidemic hazards caused by a very rapid evolution of dangerous pathogens, there is a pressing demand for bioactive textiles. Therefore, the development of high-quality knitted structures that could be used as bioactive protective materials has become a priority. This publication describes the fabrication of functional knitted structures from previously prepared antibacterial cellulose fibers containing nanosilica with immobilized silver nanoparticles. The structural and physical parameters of knitted fabrics made from them were studied with a view to their potential application in bioactive protective gloves. Tests of the basic structural and physical parameters of the knitted fabrics did not show that the nanomodifier applied in fibers significantly impacts the physical properties of the resulting fabrics. Moreover, water vapor permeability, cut resistance, and pH test results relevant to the functional and protective properties of interest and to user comfort showed that the obtained fabrics can be used in the production of bioactive protective gloves.

RESUMEN

Membrane clogging and biofilm formation are the most serious problems during water filtration. Silver nanoparticle (Agnano) coatings on filtration membranes can prevent bacterial adhesion and the initiation of biofilm formation. In this study, Agnano are immobilized via direct reduction on porous zirconia capillary membranes to generate a nanocomposite material combining the advantages of ceramics being chemically, thermally and mechanically stable with nanosilver, an efficient broadband bactericide for water decontamination. The filtration of bacterial suspensions of the fecal contaminant Escherichia coli reveals highly efficient bacterial retention capacities of the capillaries of 8 log reduction values, fulfilling the requirements on safe drinking water according to the U.S. Environmental Protection Agency. Maximum bacterial loading capacities of the capillary membranes are determined to be 3×10(9)bacterialcells/750mm(2) capillary surface until back flushing is recommendable. The immobilized Agnano remain accessible and exhibit strong bactericidal properties by killing retained bacteria up to maximum bacterial loads of 6×10(8)bacterialcells/750mm(2) capillary surface and the regenerated membranes regain filtration efficiencies of 95-100%. Silver release is moderate as only 0.8% of the initial silver loading is leached during a three-day filtration experiment leading to average silver contaminant levels of 100µg/L.

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RESUMEN

Unsatisfactory sensitivity and stability for molecules with low polarizability is still a problem limiting the practical applications of surface-enhanced Raman scattering (SERS) technique. By preparing immobilized silver nanoparticles (Fe3O4/Ag) through depositing silver on the surface of magnetite particles, a highly sensitive and selective SERS method for the detection of trace glutathione (GSH) was proposed on the basis of a system of Fe3O4/Ag nanoparticles and crystal violet (CV), in which the target GSH competed with the CV probe for the adsorption on the Fe3O4/Ag nanoparticles. Raman insensitive GSH replaced the highly Raman sensitive CV adsorbed on the surface of Fe3O4/Ag particles. This replacement led to a strong decrease of the CV SERS signal, which was used to determine the concentration of GSH. Under optimal conditions, a linear response was established between the intensity decrease of the CV SERS signal and the GSH concentration in the range of 50-700 nmol L(-1) with a detection limit of 40 nmol L(-1). The use of a Fe3O4/Ag substrate provided not only a great SERS enhancement but also a good stability, which guarantees the reproducibility of the proposed method. Its use for the determination of GSH in practical blood samples and cell extract yielded satisfactory results.

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