AAT Bioquest

Hydroxystilbamidine *CAS 223769-64-0*

Product Image
Product Image
Gallery Image 1
Ordering information
Catalog Number
Unit Size
Add to cart
Additional ordering information
InternationalSee distributors
Bulk requestInquire
Custom sizeInquire
ShippingStandard overnight for United States, inquire for international
Request quotation
Physical properties
Molecular weight472.54
Spectral properties
Excitation (nm)358
Emission (nm)433
Storage, safety and handling
Certificate of OriginDownload PDF
H-phraseH303, H313, H340
Hazard symbolT
Intended useResearch Use Only (RUO)
R-phraseR20, R21, R68
StorageFreeze (< -15 °C); Minimize light exposure


Molecular weight
Excitation (nm)
Emission (nm)
Hydroxystilbamidine (also called Fluoro Gold) is used for staining DNA and RNA. It exhibits distinctively different fluorescence emission profiles when bound to DNA compared to RNA. This cationic dye is also frequently used as a retrograde neuronal tracer. Fluoro-Gold is a trademark of Fluorochrome, Inc.

Example protocol


Biological Applications
Hydroxystilbamidine (also called Fluoro Gold) is used for staining DNA and RNA. It exhibits distinctively different fluorescence emission profiles when bound to DNA compared to RNA. This cationic dye is also frequently used as a retrograde neuronal tracer.

Spectral Properties
Excitation = 360 nm; Emission = 625 nm


Hydroxystilbamidine working solution
1 to 10% Hydroxystilbamidine in water has been successfully used. Initially, a 4% concentration is advised. If undesirable necrosis occurs at the injection site, or labeling is too intense, reduce the concentration to a 2% solution.


    The use of Hydroxystilbamidine is essentially the same as other fluorescent tracers. The main difference is that Fluoro-Gold is more flexible in terms of post-injection survival times, concentration range, tissue treatment and compatibility with other histochemical techniques. It is also more resistant to fading, brighter and more permanent than most other fluorescent tracers.

    Dye Administration
    1. Pressure injection - This is probably the most frequently used mode of application. Volumes injected range from 0.05-1 µL, typically 0.1-0.2 µL.
    2. Crystal - A crystal of the tracer can be administered from the tip of a micro-pipette. 

    Although any fixative, or no fixative, can be used, PBS containing 4% formaldehyde is most frequently employed. Fixatives containing high concentrations of heavy metals (eg. osmium, mercury) will quench the fluorescence, while high concentrations (over 1%) of glutaraldehyde may increase background fluorescence

    Histochemical Processing
    Tissue containing Hydroxystilbamidine may be processed according to virtually any common histological technique. Frozen sections of fixed tissue are most frequently used.

    Combined Methods
    At this point of processing, sections may be further processed for a second marker such as autoradiography, HRP histochemistry, immunocytochemistry, a second fluorescent tracer, fluorescent counterstain, etc.

    Mounting, Clearing and Coverslipping
    Sections are typically mounted on gelatin-coated slides, air-dried, immersed in xylene, and coverslipped with nonfluorescent DPX plastic mounting media. Sections may be dehydrated with graded alcohols, unless this is not compatible with a second tracer. If Hydroxystilbamidine is to be combined with fluorescence immunocytochemistsry, then sections are air-dried and directly coverslipped with DPX.

    Examination and Photography
    Hydroxystilbamidine can be visualized with a fluorescence microscope using a wide band ultraviolet excitation filter (excitation - 323 nm, emission - 620 nm at neutral pH). A gold color is emitted when tissue has been processed with neutral pH buffer, whereas a blue color is emitted when tissue is processed with acidic (eg. PH 3.3) pH buffer. It can be photographed digitally or with film (use Ektachrome 200-400 ASA film for color prints and comparable speed film for black and white prints). Most exposure times range from 10-60 second exposures, depending on the objective magnification and the intensity of the label. Thirty (30) second exposures are about average. Multiple exposures may be exploited to simultaneously visualize Hydroxystilbamidine and another tracer. Thus, UV would be combined with bright field illumination to simultaneously locate Fluoro-Gold with HRP or silver grains in autoradiography. Similarly, blue light excitation can be combined to also visualize the green emission color of FITC, while green excitation light may be used to simultaneously observe the red emission color of propidium iodide, or ethidium bromide (a fluorescent counterstain).


    Common stock solution preparation

    Table 1. Volume of Water needed to reconstitute specific mass of Hydroxystilbamidine *CAS 223769-64-0* to given concentration. Note that volume is only for preparing stock solution. Refer to sample experimental protocol for appropriate experimental/physiological buffers.

    0.1 mg0.5 mg1 mg5 mg10 mg
    1 mM211.622 µL1.058 mL2.116 mL10.581 mL21.162 mL
    5 mM42.324 µL211.622 µL423.245 µL2.116 mL4.232 mL
    10 mM21.162 µL105.811 µL211.622 µL1.058 mL2.116 mL

    Molarity calculator

    Enter any two values (mass, volume, concentration) to calculate the third.

    Mass (Calculate)Molecular weightVolume (Calculate)Concentration (Calculate)Moles


    Open in Advanced Spectrum Viewer

    Spectral properties

    Excitation (nm)358
    Emission (nm)433



    View all 6 citations: Citation Explorer
    Differential in vivo roles of Mpl cytoplasmic tyrosine residues in murine hematopoiesis and myeloproliferative disease
    Authors: Behrens, Kira and Kauppi, Maria and Viney, Elizabeth M and Kueh, Andrew J and Hyland, Craig D and Willson, Tracy A and Salleh, Liam and de Graaf, Carolyn A and Babon, Jeffrey J and Herold, Marco J and others,
    Journal: Leukemia (2024): 1--11
    ERG and c-MYC regulate a critical gene network in BCR:: ABL1-driven B cell acute lymphoblastic leukemia
    Authors: Behrens, Kira and Brajanovski, Natalie and Xu, Zhen and Viney, Elizabeth M and DiRago, Ladina and Hediyeh-Zadeh, Soroor and Davis, Melissa J and Pearson, Richard B and Sanij, Elaine and Alexander, Warren S and others,
    Journal: Science Advances (2024): eadj8803
    A missense mutation in the MLKL brace region promotes lethal neonatal inflammation and hematopoietic dysfunction
    Authors: Hildebrand, Joanne M and Kauppi, Maria and Majewski, Ian J and Liu, Zikou and Cox, Allison J and Miyake, Sanae and Petrie, Emma J and Silk, Michael A and Li, Zhixiu and Tanzer, Maria C and others,
    Journal: Nature communications (2020): 1--16
    Missense mutations in the MLKL ‘brace’region lead to lethal neonatal inflammation in mice and are present in high frequency in humans
    Authors: Hildebrand, Joanne M and Kauppi, Maria and Majewski, Ian J and Liu, Zikou and Cox, Allison and Miyake, Sanae and Petrie, Emma J and Silk, Michael A and Li, Zhixiu and Tanzer, Maria C and others,
    Journal: bioRxiv (2019): 628370
    Membrane-Associated RING-CH (MARCH) proteins down-regulate cell surface expression of the interleukin-6 receptor alpha chain (IL6Ra)
    Authors: Babon, Jeffrey J and Stockwell, Dina and DiRago, Ladina and Zhang, Jian-Guo and Laktyushin, Artem and Villadangos, Jose and Ching, Alan and Ishido, Satoshi and Hilton, Douglas J and Alex, undefined and er, Warren S and others, undefined
    Journal: Biochemical Journal (2019): BCJ20190577
    Inoculation of &alpha;-synuclein preformed fibrils into the mouse gastrointestinal tract induces Lewy body-like aggregates in the brainstem via the vagus nerve
    Authors: Uemura, Norihito and Yagi, Hisashi and Uemura, Maiko T and Hatanaka, Yusuke and Yamakado, Hodaka and Takahashi, Ryosuke
    Journal: Molecular Neurodegeneration (2018): 21


    View all 22 references: Citation Explorer
    Retrogradely transported fluorogold accumulates in lysosomes of neurons and is detectable ultrastructurally using post-embedding immuno-gold methods
    Authors: Persson S, Havton LA.
    Journal: J Neurosci Methods (2009): 42
    Fluorogold induces persistent neurological deficits and circling behavior in mice over-expressing human mutant tau
    Authors: He Z., undefined
    Journal: Curr Neurovasc Res (2009): 54
    A morphologic study of Fluorogold labeled tensor tympani motoneurons in mice
    Authors: Mukerji S, Brown MC, Lee DJ.
    Journal: Brain Res (2009): 59
    Organisation of the catecholaminergic system in the vagal motor nuclei of pigs: a retrograde fluorogold tract tracing study combined with immunohistochemistry of catecholaminergic synthesizing enzymes
    Authors: Chaillou E, Tillet Y, Malbert CH.
    Journal: J Chem Neuroanat (2009): 257
    Fluorogold labeling of descending brain neurons in larval lamprey does not cause cell death
    Authors: McClellan AD, Zhang L, Palmer R.
    Journal: Neurosci Lett (2006): 119
    Improved detection of fluorogold-labeled neurons in long-term studies
    Authors: Akhavan M, Hoang TX, Havton LA.
    Journal: J Neurosci Methods (2006): 156
    Tracer coupling of neurons in the rat retina inner nuclear layer labeled by Fluorogold
    Authors: Abdel-Majid RM, Archibald ML, Tremblay F, Baldridge WH.
    Journal: Brain Res (2005): 114
    Origins of lateral hypothalamic afferents associated with N-methyl-d-aspartic acid-elicited eating studied using reverse microdialysis of NMDA and Fluorogold
    Authors: Duva MA, Tomkins EM, Mor and a LM, Kaplan R, Sukhaseum A, Stanley BG.
    Journal: Neurosci Res (2005): 95
    Deficient motor innervation of the sphincter mechanism in fetal rats with anorectal malformation: a quantitative study by fluorogold retrograde tracing
    Authors: Yuan ZW, Lui VC, Tam PK.
    Journal: J Pediatr Surg (2003): 1383
    Anatomy of olivocochlear neurons in the hamster studied with FluoroGold
    Authors: Sanchez-Gonzalez MA, Warr WB, Lopez DE.
    Journal: Hear Res (2003): 65