ICG Thiol

ICG Thiol is a thiol-functionalized near-infrared cyanine dye conjugate based on indocyanine green (ICG), designed for stable attachment to thiol-reactive or thiol-compatible biomolecular and material platforms. Its strong absorption in the NIR region makes it a widely used imaging and labeling scaffold for fluorescence-based molecular imaging workflows, where NIR readout helps reduce background from visible wavelengths. In practice, the thiol functionality enables controlled incorporation into conjugates, coatings, and probe assemblies used in fluorescence microscopy, NIR fluorescence imaging, and fluorescence-guided assay development.

1. Biomolecule Conjugation

ICG Thiol is used by chemical biology and biomaterials teams to prepare fluorescent conjugates with proteins, peptides, and other thiol-bearing or thiol-reactive biomolecules. Researchers commonly incorporate the dye into labeling reagents for tracking biomolecule localization in vitro, enabling NIR fluorescence readouts in imaging and fluorescence-based binding studies. The thiol handle supports downstream coupling strategies that integrate the dye into larger constructs such as labeled affinity reagents, tracer molecules, and multicomponent imaging probes.

2. NIR Fluorescence Imaging Tracers

ICG Thiol is frequently employed to build NIR fluorescence imaging tracers for microscopy and optical imaging experiments that benefit from near-infrared excitation and emission. In research workflows, the dye is incorporated into small-molecule or macromolecular carriers to visualize distribution and uptake patterns in experimental systems, including labeled nanoparticles and polymeric assemblies. This application is especially common in laboratories developing fluorescence-guided assays and imaging reagents where NIR signal collection is used to improve contrast relative to visible fluorophores.

3. Surface Coating And Biomaterial Labeling

ICG Thiol is applied in biomaterials science to introduce NIR fluorescence functionality onto surfaces and bulk materials for imaging-guided characterization of engineered constructs. Teams use the dye-modified surfaces as fluorescent reporters to monitor material association, coating uniformity, and interaction with biomolecules in vitro. The thiol functionality is particularly useful for preparing dye-functionalized coatings and composite materials that can be interrogated by NIR fluorescence microscopy or optical fluorescence readout during materials development and performance evaluation.

4. Fluorescent Probe Construction

ICG Thiol serves as a practical dye component for fluorescent probe development, where researchers assemble NIR-active labeling modules into larger probe architectures. In fluorescence probe workflows, the thiol functionality supports incorporation into probe conjugates used to report on labeling events, distribution, or binding to engineered targets in assay formats compatible with fluorescence detection. This use case is common in assay development labs that require an NIR fluorophore scaffold for multiplexing with other optical channels or for building standardized fluorescent reagents for method development.