Polymerase Chain Reaction (PCR) and Reverse-Transcriptase PCR (RT-PCR) are DNA-amplification methods used in a variety of fields. They can be used to detect small amounts of target DNA in many types of samples, from biological samples, as in disease testing (like COVID-19 or strep throat) to forensic testing (fingerprints and crime scenes). Because DNA is double-stranded, each round of replication results in 2 copies of the sequence. This rapidly increases the amount of DNA in the sample. By using primers (small DNA molecules that tell an enzyme where to start replicating) that are specific to the signal of interest, only the relevant DNA is amplified.
Fluorescence probes are used to determine how much relevant DNA is in the sample. The fluorescent moieties are attached to short, single-stranded DNA probes that bind to specific sequences in the DNA sample. Fluorescence can be turned on or off depending on whether the DNA probe is bound to the DNA. Fluorescence intensity is proportional to the amount of the specific DNA sequence in the sample.
Nearly all fluorescence systems consist of 3 major components- an excitation light source (lamp, LED or laser), filters (to clean up the excitation wavelengths and select the emission wavelengths) and a detector. Omega has been a leader in fluorescence filters since the 1970s.
A list of stock filter sets for the common PCR dyes are listed below. These are 25 mm round for excitation and emission filters and 25.7x36 mm for dichroics designed to work at 45 degrees. We also have extensive plate stock and components available, so contact us if you have special configuration requests or you don’t see what you’re looking for here.
| Fluorophore | Ex Max (nm) | Em Max (nm) | Suggested Filter Set |
|---|---|---|---|
| SYBR green | 497 | 520 | XF404 |
| Cy-5 | 651 | 670 | XF416 |
| FAM | 494 | 520 | XF404 |
| JOE | 520 | 548 | XF405, XF402 |
| VIC | 538 | 554 | XF405, XF402 |
| HEX | 535 | 556 | XF405, XF402 |
| NED | 546 | 575 | XF405, XF402 |
| PET | 556 | 595 | XF402 |
| ROX | 575 | 602 | XF424 |
| TAMRA | 555 | 580 | XF402 |
| TET | 521 | 536 | XF405, XF402 |
| Texas Red | 595 | 615 | XF424 |