A core feature of the technology is that the reaction result may be seen with the naked eye, with
no need to open the tube to test for amplicon, and no need for expensive instrumentation to detect
reaction products. This is achieved by using a chelating reagent that is fluorescent when not quenched
by manganese ion. As pyrophosphate produced as a by-product of the LAMP reaction binds with manganese,
free calcein is released, which fluoresces under ultraviolet light. The turbidity from magnesium
pyrophosphate and calcein fluorescence allows for simple and sensitive monitoring of the LAMP
reaction using a UV-lamp and the naked eye.
See the video schematic of LAMP at Eiken's web site
LAMP employs 4 sets of primers which are complementary to six regions of the target gene: the F3c,
F2c and F1c regions at the 3' side and the B1, B2 and B3 regions at the 5' side. The FIP primer
consists of the F2 region that is complementary to the F2c region on the target gene at the 3' end,
linked to a copy of the F1c target gene sequence at the 5' end. The BIP primer consists of the B2
region that is complementary to the B2c region on the target gene at the 3' end, linked to a copy
of the B1c target gene sequence at the 5' end. The FIP and BIP primers are responsible for the
formation of loop structures. F3 and B3 are forward and backward displacement primers complementary
to the F3c and B3c regions on the target gene, respectively.
The reaction proceeds at 65°C, a temperature at which double stranded DNA is in dynamic equilibrium. This allows the LAMP primers to anneal to the complimentary sequence of double stranded target DNA, initiating DNA synthesis with the DNA polymerase with strand displacement activity displacing and releasing a single stranded DNA.
Loop primers can be added which contain sequences complementary to the single stranded loop region (between the B1 and B2 regions, or between the F1 and F2 regions) on the 5' end of the dumbbell-like structure. These primers provide an increased number of starting points for DNA synthesis, increasing the speed and quantity of target amplification, allowing for a 109 - 1010 fold increase in target DNA within 30 minutes.
