Chemical Amplification (CHAMP) by a Continuous, Self-Replicating Oligonucleotide-Based System

A self-replicating chemical system requires elements of molecular recognition, reversible self-assembly and an efficient reaction mechanism for forming next-generation templates. Polynucleotide oligomers, capable of reversible, sequence-specific duplex formation, inherently provide two of these elements and are often used in studies of such systems. Moreover, polynucleotide-based systems may be relevant to prebiotic models, and useful for nucleic acid diagnostics. Regarding the coupling mechanism, many chemical-based methods have been reported, most of which use thermally activated nucleophilic or electrophilic reagents. Typically these reagents show indiscriminate reactivity, leading to side products or inactive components, unless a "feeding" mechanism is employed where the selected reactants are supplied fresh each cycle. Photoinitiated reaction chemistry offers the advantage of selective and repeatable activation of the reactive molecule. Although there are several reports of photochemical systems with modest success in effecting template-driven photoligation, none of these achieve amplification or self-replication. Herein we report a continuous, closed tube, self-replicating chemical-based (nonenzymatic) amplification method, termed CHAMP, that is initiated by the presence of a specific nucleic acid sequence.