Ultrasensitive detection with amplification kits

Molecular Probes' Tyramide Signal Amplification (TSA) kits enable weak target signals within cells and tissues to be amplified. In immunohistochemical applications, sensitivity enhancements derived from TSA allow primary antibody dilutions to be increased in order to reduce non-specific background signals, and can overcome weak immunolabelling caused by suboptimal fixation procedures or low levels of target expression.

The lower detection threshold of TSA compared with fluorescent secondary antibodies also allows detection of two targets with primary antibodies raised in the same host species but without substantial crosstalk between the signals.

TSA is an enzyme-mediated detection method that utilises the catalytic activity of horseradish peroxidase to generate high-density labelling of a target protein or nucleic acid sequence in situ.

The signal amplification conferred by the turnover of multiple tyramide substrates per peroxidase label provides ultrasensitive detection of low-abundance targets and allows the use of smaller amounts of antibodies and hybridisation probes.

The increased sensitivity provided by TSA can be critically important for detection of short oligonucleotide probes and low abundance mRNAs by fluorescence in situ hybridisation (FISH). Optimal probe concentrations are typically 2-10 times lower for TSA FISH than for conventional immunocytochemical detection procedures.