Cycling probe technology
Cycling probe technology (CPT) was developed by ID Biomedical and licensed to Takara Biomedical Group. It involves the introduction and multiplication of probes that are specific for the organisms being sought. Each probe is a sandwich of two short DNA segments attached to the two ends of an RNA segment. The probe attaches to a single strand of target DNA. Then the RNA strand is cut into two by RNase H, a naturally occurring enzyme. The two probe halves fall away, leaving the target strand free for another probe to attach. After about 45 minutes, the probe fragments are collected and can be detected by a color change in the sample following a routine immunology-based procedure. In contrast to PCR, CPT is isothermal with the probes floating in a sample solution along with RNase at a constant temperature. Probe amplification is linear and not exponential, thus eliminating carryover contamination, and also gives a quantitative assessment of viral or bacterial load. Because a single cleavage step is involved, the test is easy and cheap to produce and can be automated.
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