Rovelyn Tapec-Dytioco | PubMed Health

PubMed2003

Ultrasensitive DNA detection using highly fluorescent bioconjugated nanoparticles.

Sensitive DNA detection is extremely important in clinical diagnostics, gene therapy, and a variety of biomedical studies. We have developed a novel DNA bioanalysis method with a 0.8 fM (0.8 x 10-15 M) detection limit using a bioconjugated fluorescent nanoparticle-based sandwich assay. An organic dye silica nanoparticle is synthesized using a modified reverse microemulsion. The nanoparticles are highly fluorescent, extremely photostable, and easy for bioconjugation for bioanalysis. They exhibit an excellent signaling ability in the presence of trace amounts of DNA targets. With an effective surface modification, nonspecific binding and nanoparticle aggregation are minimized. In addition, the nanoparticle-based DNA bioanalysis assay can effectively discriminate one-base mismatched DNA sequences. We expect this nanoparticle-based assay to be widely useful in a number of biomedical applications where reproducible, selective, and ultrasensitive gene analysis is critical.

Base Sequence↗

PubMed2003

Collection of trace amounts of DNA/mRNA molecules using genomagnetic nanocapturers.

The collection and then the separation of rare DNA/mRNA targets with single-base mismatches in a complex matrix is critically important in human disease diagnostics, gene expression studies, and gene profiling. The major result of this work is the development and application of a novel genomagnetic nanocapturer (GMNC) for the collection, separation, and detection of trace amounts of DNA/RNA molecules with one single-base difference. The GMNC is constructed by bioconjugating molecular beacon DNA probes onto magnetic nanoparticle surfaces. We have successfully applied the GMNC in artificial buffer solution samples and in cancer cell samples, both containing different proteins and random DNA sequences. Our method has three distinctly useful features: highly efficient collection of trace amount of DNA/mRNA samples down to femtomolar (10(-15) M) concentrations; excellent ability to differentiate single-base-mismatched DNA/mRNA samples by combining the exceptional specificity of molecular beacons and the separation power of magnetic nanoparticles; and real-time monitoring and confirmation of the collected gene products. The newly developed genomagnetic nanocapturers will be highly useful for the collection of trace amounts of DNA/mRNA targets in a variety of sample sources in forensic, medical, and biotechnological fields.

Actins↗