An amplification technology for improving sensitivity when measuring components in biological samples

A carbohydrate biosensor surface for the detection of uropathogenic bacteria

We have developed a new surface for use in biosensors that is based on a gold plate covered with a specific carbohydrate receptor structure. The carbohydrate, Gal alpha 1-4Gal, was bound covalently via a thioalkylcarboxy-spacer, or adsorbed as a neoglycoprotein, to a two-dimensional gold surface. Both types of surfaces showed high specificity in the binding of the uropathogenic bacteria P-fimbriated Escherichia coli compared to the binding of non-infectious bacteria. The signal to noise ratio is sufficiently high to allow specific detection of the bacteria in biosensor applications.

Phagocytosis of protein coated colloidal-gold-agarose-gelatin microbeads by cultured uterine glandular epithelial and stromal cells

A procedure for fixing and immunostaining whole cells from primary cultures of ovine and bovine uterine gland fragments was used to identify keratin in intermediate filaments of epithelial cells to distinguish them from stromal cells. Colloidal gold encapsulated agarose-gelatin microbeads were coated with different proteins and used to investigate uptake by epithelial and stromal cells in culture. Microbeads were taken up by stromal cells and by epithelial cells on the outskirts of colonies. These cells formed ridges where they contacted and grew above stromal cells. Electron microscopy demonstrated that the microbeads had been internalized and appeared to be nontoxic. Individual cells could harbor more than 90 microbeads within their cytoplasm for at least seven to ten days with no apparent harm. Some cells with microbeads were seen to divide.

Preparation of nanoparticles conjugated with enzyme and antibody and their use in heterogeneous enzyme immunoassays

Enzyme conjugates suitable for enzyme-linked immunosorbent assays can be conveniently prepared by binding enzyme and antibody to nanoparticles. Peroxidase and antitransferrin or anti-alpha-fetoprotein were co-immobilized to tresyl activated 40 nm silica particles and the particle conjugates used in heterogeneous enzyme immunoassays for the evaluation of transferrin and alpha-fetoprotein within the concentration range 0.25-1000 ng/ml.