Infrared dyes are specialized dyes that absorb and emit light in the infrared (IR) region of the electromagnetic spectrum, typically the near-infrared (NIR) region. This property makes them incredibly useful in various applications, particularly in biological imaging and medical diagnostics. Unlike visible light, IR light penetrates tissues more deeply, resulting in enhanced sensitivity and clearer images with less background interference.
Why Use Infrared Dyes?
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Reduced Background Autofluorescence: NIR dyes provide a superior signal-to-noise ratio because biological samples have significantly lower autofluorescence (self-luminescence) in the near-infrared region. This leads to clearer images and more accurate data. [Referencing: IRDye Infrared Fluorescent Dyes and near-infrared (NIR) fluorescence imaging deliver enhanced sensitivity due to low background autofluorescence in the near-infrared region and, therefore, higher signal-to-noise ratios.]
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Improved Tissue Penetration: The longer wavelengths of IR light allow for deeper penetration into tissues compared to visible light, enabling visualization of deeper structures within living organisms. [Referencing multiple sources mentioning improved tissue penetration and in vivo applications of NIR dyes].
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Enhanced Sensitivity: The combination of reduced autofluorescence and improved penetration contributes to dramatically higher sensitivity in various assays and imaging techniques. [Referencing: IRDye Infrared Fluorescent Dyes Deliver Enhanced Sensitivity].
Types and Applications of Infrared Dyes:
Several types of IR dyes are available, each with specific properties and applications:
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IRDye 680RD: A popular NIR dye used extensively in small animal imaging, Western blotting, and In-Cell Western assays. [Referencing: IRDye 680RD is the near-infrared fluorescent dye of choice for small animal imaging, Western blot, and In-Cell Western Assay applications in the 700nm channel. ]
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IRDye 680RD DBCO: A variation of IRDye 680RD designed for copper-free click chemistry, enabling labeling of live cells, whole organisms, and non-living samples. [Referencing: IRDye 680RD Dibenzocyclooctyne Infrared Dye is used to perform copper-free click chemistry with live cell, whole organisms, and non-living samples.]
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Near-IR CF® Dyes: A next-generation of long wavelength dyes offering superior performance compared to other commercially available NIR dyes. [Referencing: Near-IR CF® Dyes are next-generation long wavelength dyes that offer superior performance over other commercially available near-IR dyes.]
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Indocyanine Green (ICG): An FDA-approved near-infrared dye exhibiting significant shortwave IR (SWIR) emission suitable for advanced SWIR imaging. [Referencing: We show that commercially available NIR dyes, including the FDA-approved contrast agent indocyanine green (ICG), exhibit optical properties suitable for in… and We show that indocyanine green, a clinically approved near-IR dye, exhibits a remarkable amount of SWIR emission, which enables state-of-the-art SWIR imaging. ]
Numerous other specialized NIR dyes are being developed, such as those with improved photostability, enhanced absorption/emission properties, and tailored chemical structures for specific applications. These developments are pushing the boundaries of bioimaging and medical diagnostics. [Referencing sources mentioning novel NIR dyes with improved properties].
Examples of practical uses include:
- Preoperative surgical guidance: NIR dyes enable improved visualization of tumors or other anatomical structures during surgery. [Referencing: Preoperative CT-Guided Near-Infrared Dye Marking for…]
- In vivo imaging: Studying biological processes and drug delivery within living organisms.
- Diagnostics: Improving sensitivity and accuracy of various diagnostic assays.
