Black Hole Quencher® Dyes

Since their introduction to the DNA marketplace in 2000, the Black Hole Quenchers have become THE quencher of choice used in qPCR probes and other FRET applications.

We introduced the Black Hole Quencher® (BHQ®) dyes in 2000 and since then they have become the quencher of choice for qPCR probes and for other fluorescence-quenched probe applications. When fluorogenic dual-labeled probes were first introduced, quenchers were often a second reporter dye, typically TAMRA. The sensitivity of these probes, such as FAM-TAMRA, is limited because the fluorescence from TAMRA can leak into the channel meant to detect FAM fluorescence. Dark quenchers, which are dyes with no native fluorescence, offer a solution to this problem.

The BHQ dyes are true dark quenchers with no native emission due to their polyaromatic-azo backbone. Substituting electron-donating and withdrawing groups on the aromatic rings produces a complete series of quenchers with broad absorption curves that span the visible spectrum.

bhq absorption curves

Normalized absorption spectra of the BHQ dyes
illustrate their range of quenching through FRET

BHQ dyes work through a combination of FRET and static quenching to enable researchers to avoid the residual background signal common to fluorescing quenchers such as TAMRA, or low signal to noise ratio.

These quenchers can be paired with all common reporter dyes to construct efficiently quenched qPCR probes for multiplexing assays. In addition to quenching by FRET, BHQ dyes have also been shown to efficiently quench fluorescence through static quenching via formation of a ground state complex with the reporter dye.

Learn more about the difference between static and FRET quenching.

BHQ quenchers have broad absorption spectra and can be paired with reporter dyes that emit in the following ranges:

  • BHQ-0: 430-520 nm
  • BHQ-1: 480-580 nm
  • BHQ-2: 560-670 nm
  • BHQ-3: 620-730 nm
  • BHQ-10 480-550nm Water Soluble (WS)

Download our Black Hole Quencher and Dye Selection Chart for more details about other offered dyes.

Black Hole Quencher Dual-Labeled Probes

As inventors of the Black Hole Quencher (BHQ) dyes, every probe format is available as a BHQ dye labeled oligo. In addition, each oligo may be labeled with a variety of other fluorophores such as FAM, TET, HEX, JOE, CAL Fluor®,Quasar®,and Pulsar® dyes.
BHQ Probes

Black Hole Quencher DNA Synthesis Reagents

LGC Biosearch offers Black Hole Quenchers for synthesizing dual labeled oligonucleotides. Our BHQ dyes are available for 3’, internal and 5’ modifications.

Black Hole Quencher Peptide Labeling Reagents

LGC Biosearch offers Black Hole Quenchers for labeling peptides. All of our BHQ dyes are available as carboxylic acid or succinimidyl esters. Our BHQ-1 and BHQ-2 dyes are available as FMOC lysine conjugates. Our water soluble BHQ-10 is available as a carboxylic acid or succinimidyl ester.
Black Hole-Quencher-Labeling-Reagents