Quasar770 NHS Ester

Quasar770 NHS Ester is an NHS-ester activated fluorophore designed for covalent attachment to primary amines on proteins, peptides, and other amine-containing biomolecules. As a far-red emitting labeling reagent, it is commonly used to build fluorescence conjugates for microscopy and fluorescence-based assays where reduced background and deep-tissue-compatible imaging channels are advantageous. The activated N-hydroxysuccinimide group enables straightforward reagent-to-conjugate workflows for creating stable amide-linked bioconjugates.

1. Protein Conjugation Labeling

Quasar770 NHS Ester is widely used to fluorescently label antibodies, antibody fragments, enzymes, serum proteins, and protein standards for downstream fluorescence imaging and assay development. Researchers typically incorporate the dye into protein conjugates to generate far-red probes for binding studies, immunoassays, and fluorescence readouts where excitation/emission into the red spectral window helps separate signal from autofluorescence. Because the NHS ester reacts with lysine side-chain amines and N-termini, it supports rapid preparation of amide-linked labeling reagents for characterizing biomolecular interactions, tracking protein localization in fixed samples, or producing fluorescent controls for assay optimization.

2. Fluorescence Microscopy Tracing

Quasar770 NHS Ester is used in fluorescence microscopy workflows to visualize labeled biomolecules in cellular and biomaterial contexts, including staining of protein targets and fluorescent tracking of conjugated ligands. Far-red emission is often leveraged for multi-color experiments and for imaging setups that include red-channel detection, helping reduce interference from common green/yellow autofluorescence. In practice, the reagent is frequently applied to generate microscopy-compatible conjugates for imaging workflows where conjugate stability and covalent attachment to amine-bearing targets are important for wash-intensive protocols.

3. Flow Cytometry Antibody Staining

Quasar770 NHS Ester supports fluorescence labeling strategies for flow cytometry, particularly when far-red detection channels are used to improve spectral separation in multiplex panels. Flow cytometry users commonly prepare Quasar770-labeled antibodies or protein reagents by coupling the NHS ester to amine-containing biomolecules, enabling fluorescent staining of cell-surface or intracellular targets after fixation/permeabilization workflows. The covalent labeling approach helps maintain consistent staining performance across experiments and provides a robust fluorophore choice for panel design where minimizing bleed-through from other fluorophores is a key consideration.

4. Fluorescent Bioassay Reagent Building

Quasar770 NHS Ester is used to construct fluorescence-ready assay reagents, including labeled enzymes, affinity reagents, and assay controls for plate-based fluorescence measurements. In research and industrial assay development, the dye is commonly incorporated to generate tracer conjugates used in binding assays, secondary detection reagents, and fluorescence monitoring steps that benefit from far-red readout. The NHS-ester chemistry enables rapid conversion of amine-containing biomolecules into stable fluorescent reagents, supporting reproducible assay reagent preparation for screening, method development, and quality control of fluorescence-based workflows.