Lisa R. Hilliard

Immobilization of oligonucleotides onto silica nanoparticles for DNA hybridization studies

Abstract This paper describes the development of oligonucleotide-functionalized nanoparticles. We used disulfide-coupling chemistry for the immobilization of oligonucleotides onto silica nanoparticles and subsequently demonstrated the properties of the resulting DNA nanoparticles. Factors influencing the immobilization and hybridization processes were examined and optimized. The oligonucleotide-modified silica nanoparticles provide an efficient substrate for hybridization and can be used in the development of DNA biosensors and biochips.

Ultrasensitive DNA and protein analysis using molecular beacon probes

Molecular beacons (MBs) are novel nucleic acid hairpin-shaped probes that brightly fluoresce when they are bound to their targets and have a significant advantage over conventional nucleic acid probes. We have developed ultrasensitive MB DNA biosensors, including a fiber optic evanescent wave sensor and a submicrometer optical fiber sensor. The fiber optic sensors are rapid, stable, reproducible, regenerable and have the capability for one base mismatch discrimination. The sensors have been applied for both detection of DNA and specific mRNA sequences. A sensor array has also been demonstrated for multiple target identification. A microwell array methodology has been developed for ultrasmall amount DNA analysis, and can detect 50 DNA molecules in each well. Our study has also extended the applications of MBs from pure nucleic acid hybridization to DNA-protein interactions. These recent advancements of ultrasensitive DNA/protein analysis by molecular beacon probes provide a powerful tool for genomics and proteomics studies, molecular diagnoses of diseases, and new drug development.