Loop-mediated isothermal amplification
[9] Dyes, such as SYBR green, can be used to create a visible color change that can be seen with the naked eye without the need for expensive equipment, or for a response that can more accurately be measured by instrumentation.
Dye molecules intercalate or directly label the DNA, and in turn can be correlated with the number of copies initially present.
[11][12] pH-dependent dye indicators such as Phenol Red induce a color change from pink to yellow when the pH value of the reaction decreases upon DNA amplification.
[13] However, the pH-change dependent readout requires a weakly buffered reaction solution, which poses a great challenge when using crude sample inputs with variable pH.
[13] LAMP is a relatively new DNA amplification technique, which due to its simplicity, ruggedness, and low cost could provide major advantages.
[14] Because LAMP is isothermal, which eradicates the need for expensive thermocyclers used in conventional PCR, it may be a particularly useful method for infectious disease diagnosis in low and middle income countries.
[15] LAMP is widely being studied for detecting infectious diseases such as filariasis,[16] Zika Virus,[17] tuberculosis,[18] malaria,[19][20][21] sleeping sickness,[22] and SARS-CoV-2.
[27] This feature of LAMP may be useful in low-resource or field settings where a conventional DNA or RNA extraction prior to diagnostic testing may be impractical.
Researchers have also been able to add factors to make identification even more simple including metal-indicator dye and phenol red to be able to use a smartphone and the naked eye respectively to analyze the results.
Multiplexing in LAMP has been achieved by choosing a target region with a restriction site, and digesting prior to running on a gel, such that each product gives rise to a distinct size of fragment,[32] although this approach adds complexity to the experimental design and protocol.
This method employs a conventional LAMP primer set to exponentially amplify the target sequence, followed by the hybridization of a ribonucleotide-containing fluorescent probe to the amplification product.
