Nucleic Acid Amplification Technique for Rapid Diagnostic Analysis

CDC researchers developed a simple target-specific isothermal nucleic acid amplification technique, termed Genome Exponential Amplification Reaction (GEAR). The method employs a set of four primers (two inner and two outer). The outer primer pair targets three specific nucleic acid sequences at a constant 60°C, while the inner pair of primers accelerates and improves the sensitivity of the assay. The GEAR technique is an improvement over loop-mediated isothermal amplification (LAMP) in three ways. First, the GEAR method uses two Tab primers which target three genomic regions (corresponding LAMP primers target four regions). Second, the GEAR method features complementary 5' ends between the forward and reverse primers. Third, the GEAR method does not require a second set of outer primers (LAMP requires two outermost primers). Additionally, the GEAR isothermal method can be performed in a relatively inexpensive water bath or heating block, with detection of amplification products by fluorescence, thus making it suitable for low resource settings.