Notwithstanding the impending development of a new generation of robotics-based instrumentation for DNA sequencing, the technology applied to deciphering the human genome-namely electrophoretic separation of fluorescently-tagged oligonucleotides-is old, and it is unclear whether the task can be accomplished by the 2005 using these methods. Accordingly, a radically new approach to DNA sequencing requiring neither fluorescently-labeled nucleotides nor separation is proposed. Based on surface plasmon resonance (SPR), a technique that has already gained acceptance and widespread use by the biochemical community, the concept is to monitor the distance of a colloidal Au- tagged DNA polymerase from the from the surface of a DNA-derivatized SPR chip during replication. Incorporation of complementary nucleotides leads to movement of the colloidal Ad:DNA polymerase complex along single-stranded DNA, which is then detected as a change in reflectivity. The scientific basis for this new technology is the extraordinarily large effect on Au thin film reflectivity caused by proximity of colloidal Au nanoparticles, an effect that has already been exploited by the PI through development of ultrasensitive colloidal Au-amplified immunoassays based on SPR. If the work proposed herein is fully successful, i.e. if the concept of ultrarapid DNA sequencing is demonstrated both in single-channel and multi-channel SPR instruments, the entire human genome can be sequenced in just over one year.
