DNA Biosensors Using Morpholino Oligos
presentationposted on 21.07.2014, 00:00 by Josh McConnell
Advancements in Surface Enhanced Raman Spectroscopy (SERS) have made devices capable of sensing a particular sequence of DNA in minutes. Applications of these devices include rapid identification of disease, possibly before symptoms arise, and the detection of biological agents. If practical use of such sensors is executed many false diagnoses can be avoided given the device is used for medical purposes and can ensure an efficient response to a biological attack. One of the factors limiting the sensitivity of DNA sensing devices is the high buffer concentration required, which contributes to noise in SERS spectra. A strong buffer concentration is necessary because the negative charge of the DNA probe and target DNA needs to be sufficiently screened in order for bonding, and thus detection of the target DNA, to occur. Theoretically, the use of morpholinos, uncharged DNA analogues, would allow for the use of a low salt concentration buffer, eliminating much of the noise associated with high salt concentrations. In our study, the effectiveness of morpholino oligomers as signaling and tethering probes under various buffer concentrations was examined using Quartz Crystal Microbalance with Dissipation. In addition, the enhancements of gold or silver nanoparticle-coated silica substrates were quantified using SERS spectroscopy.