Leon isothermal amplification
Leon is a rapid DNA amplification technology. Leon is an isothermal amplification reaction that can challenge the industry standard Polymerase Chain Reaction (PCR) for the number of copies made within a short period of time.
The following is a graphical description of how Leon works. Leon starts with two primers that attach themselves to their designed positions on the cDNA at each end of the target sequence, followed by two complementary enzymes that then copy the target between the primers multiple times.
A schematic of the Leon technology
The key differences between Leon and PCR are graphically illustrated below in this depiction of the temperature changes needed by both the Leon and PCR amplification systems which shows how Leon is both simpler and faster. Leon amplifies the starting DNA molecule numbers by at least 60,000 times within 10 minutes. To do this, Leon is kept at one stable temperature. PCR based systems need 48 temperature changes for the same degree of amplification. PCR needs to go through about 16 temperature cycles to match a similar 60,000 fold amount of amplification. PCR therefore takes some 40 minutes to complete a similar amplification. Leon is therefore 30 minutes faster than PCR for the 60,000 times amplification required that brings the molecule numbers up to the level that allows detection systems to function.
Leon and PCR temperature profiles compared
As illustrated above, the Leon isothermal reaction is a simpler process than thermal cycling. For comparison purposes, in this illustration we have compared both PCR and Leon starting from RNA rather than DNA. The first step in both processes is the creation of cDNA from the RNA. This takes some 10 minutes. In the case of Leon, this RNA to cDNA conversion is conducted in the same test tube with the Leon amplification reagents just being added in later as a follow on stage. In the case of the PCR amplification, the conversion of RNA into cDNA has to be performed in two separate steps. The isothermal amplification of Leon only requires one change in temperature from a steady 48OC to a steady 95OC halfway through the whole process. The industry standard amplification system is based on the Polymerase Chain Reaction (PCR) which needs multiple regular rapid temperature swings through three temperatures (thermal cycling) to drive the doubling of the number of copies at each cycle of the whole process. Thermal inertia of the test tube contents often restricts cycle times, which slows down PCR systems generally.
The following is a summary of the competitive advantages of the proprietary Leon chemistry.