CHP enables facile, sensitive and specific detection of collagen bands in SDS-PAGE gels, through its triple-helical hybridization with the collagen chains denatured by SDS and heating during electrophoresis. The simple procedure eliminates the need for western blot (e.g., protein transferring to membranes and blocking), saving time, efforts and materials.
Fluorescent F-CHP reliably measures a dilution series of type I collagen directly in an SDS-PAGE gel, and detects a band containing as little as 5 ng of protein (left). CHP identifies multiple collagen types (middle) and has no affinity to non-collagenous molecules in the ECM (middle) and cell lysate (right) due to its neutral and hydrophilic nature. Fluorescence images recorded with a Typhoon Imager (λex: 488 nm). Images were adapted from ref  with permission.
In addition, CHP can be used in replacement of unsuccessful collagen antibodies or conventional collagen stains to detect collagen in highly denatured tissues. Images below show complete collagen content in a thoroughly heated porcine ligament section visualized by F-CHP or B-CHP (further detected by HRP-conjugated NeutrAvidin). CHP stain offers higher specificity to collagens than conventional collagen stains such as Sirus Red, which relies on positive charges for collagen binding and can stain other proteins with high content of basic amino acids nonspecifically.
- Direct detection of collagenous proteins by fluorescently labeled collagen mimetic peptides. Bioconjugate Chemistry (2013) more info
- Sirius red and acid fuchsin staining mechanisms. Biotechnic & Histochemistry (1998) 73, 71–77.