Magneto immuno-PCR: a novel immunoassay based on biogenic magnetosome nanoparticles.

We describe an innovative modification of the Immuno-PCR technology for automatable high sensitive antigen detection. The Magneto Immuno-PCR (M-IPCR) is based on antibody-functionalized biogenic magnetosome nanoparticles revealing major advantages over synthetic magnetic particles. The general principle of the M-IPCR is similar to that of a two-sided (sandwich) immunoassay.

Preparation, structural, and optical features of two-dimensional cross-linked DNA/gold-nanoparticle conjugates.

The formation and the optical features of two-dimensional aggregates formed by DNA-directed immobilization and cross-linking of bifunctional DNA-gold nanoparticles at flat gold substrates are analyzed. The samples are structurally characterized by atomic force microscopy to evaluate the particle size, the particle densities, and the degree of aggregation. The optical characteristics determined by UV/visible measurements are correlated with the structural features observed.

Synthesis and characterization of deoxyribonucleic acid-conjugated gold nanoparticles.

Gold nanoparticles functionalized with thiol-modified single-stranded oligonucleotides are highly useful reagents for a variety of applications, ranging from materials science to bioanalytics. In this chapter, the preparation of citrate stabilized 15-nm Au nanoparticles is described. The nanoparticles are conjugated with 3'-thiol-modified deoxyribonucleic acid oligomers and the resulting conjugates are characterized by determining their shape, size, and surface coverage.

Bifunctional DNA-gold nanoparticle conjugates as building blocks for the self-assembly of cross-linked particle layers.

The DNA-directed self-assembly of surface-bound layers of gold nanoparticles offers a broad range of applications in biomedical analyses as well as in materials science. We here describe a new concept for the assembly of substrate-bound nanoparticle monolayers which employs bifunctional nanoparticles as building blocks, containing two independently addressable DNA oligomer sequences. One of the sequences was utilized for attaching the particle at the solid support, while the other sequence was used to establish cross-links between adjacently immobilized particles.

"Belt and braces": a peptide-based linker system of de novo design.

A new self-assembling peptide-based linker is described. The system comprises three leucine-zipper sequences of de novo design: one peptide, "the belt", templates the co-assembly of the other two-half-sized peptides, "the braces". These basic features were confirmed by circular dichroism spectroscopy and analytical ultracentrifugation: when mixed, the three peptides reversibly formed a predominantly helical and stable 1:1:1 ternary complex.