Detection of Saccharomyces cerevisiae by silver nanoparticles sensitized with various lectins.

Anisotropic silver nanoparticles sensitized by various lectins were applied for detection of yeast (Saccharomyces cerevisiae) which was used as a model of fungal cells. It was shown that high concentrations of yeast cells have stabilized silver nanoparticles, preventing their aggregation in the presence of NaCl whereas at low concentrations of cells, the salt has induced aggregation of nanoparticles with drastic changes in optical spectra. These changes depend on cell concentration and permit the detection of cells in the range from 3.2 × 103 to 7 × 107 cell per ml. This approach was used for the determination of these cells in urine and its applicability was demonstrated.

Antibodies to oxidized lipoproteins in human normal plasma, detection and analysis.

In the article, presence of antibodies to protein components of oxidized human donor plasma was demonstrated. It was shown that normal plasma oxidized by CuCl2, FeSO4, or potassium ferricyanide acquired ability to bind with human IgG-sensitized polystyrene latex particles and colloidal gold nanoparticles. Ability of these antibodies to bind to oxidized components strongly depends on time of oxidation. Moreover, Sepharose 2B conjugated with human IgG has affinity to component of such plasma. Molecular weight analysis demonstrates that this component eluted as a single peak in size exclusion chromatography with molecular weight about 3 × 106 Da.

Anisotropic silver nanoparticles sensitized by oxidized lipoproteins for detection of appropriate antibodies.

Antibodies to oxidized lipoproteins are useful markers for diagnosis and prognosis of some heart diseases. Low density lipoproteins (LDL) were purified from human plasma and were oxidized by CuCl2. They were immobilized on anisotropic silver nanoparticles with tunable plasmon resonance band and were applied for detection of appropriate antibodies in sera of patients with stenosis. The presence of such antibodies brings to significant shifting of plasmon resonance band to long-wave region in comparison with control sera. This approach permits to detect such antibodies by rapid method with one step procedure.

Wheat germ agglutinin and Lens culinaris agglutinin sensitized anisotropic silver nanoparticles in detection of bacteria: A simple photometric assay.

Efficacy of anisotropic silver nanoparticles sensitized with wheat germ agglutinin (WGA) and Lens culinaris agglutinin (LCA) was studied for detection of Staphylococcus aureus and Escherichia coli. It was demonstrated that interaction of these nanoparticles with bacteria stabilizes them and prevents their aggregation upon addition of sodium chloride; such stabilization depends on bacteria concentration. High concentration of bacteria results in higher stabilization whereas low concentration leads to aggregation of nanoparticles. Optical changes as a result of aggregation correlate with bacteria concentration. The developed approach allows the detection of Gram-positive bacteria (S.aureus) with the lowest detectable concentration of 103 cells/mL and Gram-negative bacteria (E. coli) with the lowest detectable concentration of 3 × 103 cells/mL using WGA-sensitized nanoparticles. In the case of LCA-sensitized nanoparticles the lowest detection was 5 × 103 cells/mL for S. aureus and 5 × 104 cells/mL for E. coli.