• The currently available and widely used metal based small molecule fluorescent probes are FlAsH or its analogues such as ReAsH, SplAsH etc.
• Though, these probes must be used with EDT to increase rate of labeling and to reduce the background.
• Further, they use arsenic and can only label tetracysteine fused proteins.
• Arsenic is toxic to human, and is also an environmental contaminant. Moreover, tetracysteine motif is not common tetracysteine motif is not as common as His-tag to be genetically fused to proteins in cell biology and biomedical research.
• Therefore, extensive research has been carried out to image His-tagged proteins, however these probes have poor permeability.

• The invention describes metal chelation-based fluorescent probes for imaging intracellular proteins or other biomolecules in live cells to monitor their biological events.
• The probes uses nickel(II) and nitrogen containing ligand(s) to label poly-histidine-tagged proteins/biomolecules or endogenous metal-binding proteins.
• They also are able to covalently bind to labeled proteins, enabling further protein identification.

Advantages

• High permeability to cell membrane.
• Doesn't require support of penetrating peptide, catalyst, or other chemicals to enter the cell.
• Lower cost.
• Higher binding affinity because of the introduction of a second binding site.
• Higher signal intensity because of closer proximity to the interested protein.
• Less toxic than the arsenic type probes like FlAsH and ReAsH.
• Simple synthetic route.

• Probes for visualization for protein expression and purification in biology and biomedical research.
• Probes for visualization and identification of metalloproteomes in a high-throughput manner.

• Granted Patent in Australia, issued on 14 September, 2017.
• Undergoing examination in China, US, Hong Kong, Japan,  and Canada.
• Prototype available.