US 2003/0157538 A1 · Nucleic acid biosensor diagnostics

Abstract

A biosensor for direct analysis of nucleic acid hybridization by use of an optical fiber functionalized with nucleic acid molecules and fluorescence transduction is disclosed. Nucleic acid probes are immobilized onto the surface of optical fibers and undergo hybridization with complementary nucleic acids introduced into the local environment of the sensor. Hybridization events are detected by the use of fluorescent compounds which bind into nucleic acid hybrids. The invention finds uses in detection and screening of genetic disorders, viruses, and pathogenic microorganisms. Biotechnology applications include monitoring of gene cultures and gene expression and the effectiveness (e.g. dose-response) of gene therapy pharmaceuticals. The invention includes biosensor systems in which fluorescent molecules are connected to the immobilized nucleic acid molecules. The preferred method for immobilization of nucleic acids is by in-situ solid phase nucleic acid synthesis. Control of the refractive index of the immobilized nucleic acid is achieved by the support derivatization chemistry and the nucleic acid synthesis. The preferred optical fiber derivation yields a DNA coating of higher refractive index than the fiber core onto the fiber surface.

Claims30

Dependent claims

A biosensor for detecting a target nucleic acid in the presence of a fluorophore by detection of fluorescence from the fluorophore which comprises:

(a) an optical element having an index of refraction and which comprises an interaction surface;
(b) an immobilized layer having an index of refraction which comprises a nucleic acid or nucleic acid analogue covalently attached to the interaction surface of the optical element, the nucleic acid or nucleic acid analogue capable of hybridizing to the target nucleic acid to form a hybridized nucleic acid complex;
(c) a light source for introducing light capable of stimulating fluorescence of the fluorophore into the optical element in contact with the interaction surface;
and
(d) a detector for detecting fluorescence emitted by the fluorophore on binding to a hybridized nucleic acid complex;
wherein the index of refraction of the immobilized layer is equal to or greater than the refractive index of the interaction surface of the optical element such that direct excitation of the fluorophore in the immobilization layer to emit fluorescence results in the detection of the target nucleic acid, wherein the nucleic acid or nucleic acid analogue is attached to the interaction surface through a linker molecule that is at least about 25 Å in length and the index of refraction of the immobilized layer is controlled by changing the density of linker molecules immobilized on the interaction surface of the optical element and wherein the linker contains ethylene glycol subunits.

3 more elements

Dependencies are inferred from the claim text.

Nucleic acid biosensor diagnostics

Life of this patent

Nucleic acid biosensor diagnostics

Life of this patent

Abstract

Claims30