Quasar 670 NHS | CAS 1469777-63-6

Quasar 670 NHS is an NHS-ester activated fluorophore designed for covalent attachment to primary amines in proteins, peptides, and antibody conjugates. As a far-red emitting dye, it is commonly used to build stable fluorescence labels for imaging and assay development workflows where reduced background and compatibility with red-channel detection are important.

1. Protein Conjugation Labeling

Quasar 670 NHS is widely used by protein engineering and chemical biology groups to generate fluorescently labeled antibodies, affinity reagents, and protein standards through NHS-ester coupling to lysine residues and N-terminal amines. In practice, researchers incorporate the dye into labeling pipelines for immunofluorescence reagent preparation, fluorescence-based binding assays, and calibration materials for instrument setup. The activated ester format supports straightforward conjugate preparation for downstream microscopy and plate-reader workflows that monitor far-red fluorescence.

2. Biomolecule Imaging Probes

Quasar 670 NHS serves as a practical labeling handle for constructing far-red fluorescence imaging probes from amine-containing biomolecules, including peptides, enzyme conjugates, and protein scaffolds used in targeted or non-targeted cellular studies. Teams performing fluorescence microscopy and multicolor imaging often select this dye to place signal into a red/far-red channel, enabling separation from green and orange fluorophores used in parallel. The NHS-ester chemistry also supports conjugate generation for probe libraries used in localization studies, colocalization experiments, and imaging reagent development.

3. Flow Cytometry Reagent Building

Quasar 670 NHS is used in flow cytometry workflows to prepare far-red fluorescent conjugates for labeling cell-surface proteins, tracking binding interactions, and generating fluorescence standards for gating and compensation strategies. Research groups typically couple the dye to amine-containing targeting reagents such as antibodies, antibody fragments, or protein ligands, then apply the resulting conjugates in staining workflows compatible with far-red detection. This labeling approach is especially common when a robust red-channel reporter is needed for multiplex panels.

4. Fluorescence Bioassay Development

Quasar 670 NHS supports fluorescence assay development by enabling covalent tagging of assay components that report binding, immobilization, or reagent presence via far-red readout. In biochemical and materials research, labeled proteins prepared from NHS-ester coupling are used to build fluorescence-based detection reagents for plate assays, bead-based workflows, and imaging-compatible screening formats. The dye's activated ester functionality helps streamline reagent construction for assay development teams that require consistent conjugate preparation from amine-bearing biomolecules.