logo
AAT Bioquest

iFluor® 800 maleimide

In vivo fluorescence imaging uses a sensitive camera to detect the fluorescence emission from fluorophores in whole-body living small animals. To overcome the photon attenuation in living tissue, fluorophores with long emission at the infrared (IR) region are generally preferred. Recent advances in imaging strategies and reporter techniques for in vivo fluorescence imaging include novel approaches to improve the specificity and affinity of the probes and to modulate and amplify the signal at target sites for enhanced sensitivity. Further emerging developments aim to achieve high-resolution, multimodality, and lifetime-based in vivo fluorescence imaging. Our iFluor® 800 is designed to label proteins and other biomolecules with infrared fluorescence. Conjugates prepared with iFluor® 800 have excitation and emission in the IR range. iFluor® 800 dye emission is well separated from commonly used far-red fluorophores such as Cy5, Cy7, or allophycocyanin (APC), facilitating multicolor analysis. This fluorophore is also useful for small animal in-vivo imaging applications or other imaging applications requiring IR detection. iFluor® 800 maleimide is thiol-reactive and can be readily used to conjugate thiol-containing biomolecules.

Example protocol

PREPARATION OF STOCK SOLUTIONS

Unless otherwise noted, all unused stock solutions should be divided into single-use aliquots and stored at -20 °C after preparation. Avoid repeated freeze-thaw cycles.

1. iFluor™ 800 maleimide stock solution (Solution B)
Add anhydrous DMSO into the vial of iFluor™ 800 maleimide to make a 10 mM stock solution. Mix well by pipetting or vortex.
Note     Prepare the dye stock solution (Solution B) before starting the conjugation. Use promptly. Extended storage of the dye stock solution may reduce the dye activity. Solution B can be stored in freezer for upto 4 weeks when kept from light and moisture. Avoid freeze-thaw cycles.


2. Protein stock solution (Solution A)
Mix 100 µL of a reaction buffer (e.g., 100 mM MES buffer with pH ~6.0) with 900 µL of the target protein solution (e.g. antibody, protein concentration >2 mg/mL if possible) to give 1 mL protein labeling stock solution.
Note     The pH of the protein solution (Solution A) should be 6.5 ± 0.5.
Note     Impure antibodies or antibodies stabilized with bovine serum albumin (BSA) or other proteins will not be labeled well.
Note     The conjugation efficiency is significantly reduced if the protein concentration is less than 2 mg/mL. For optimal labeling efficiency the final protein concentration range of 2-10 mg/mL is recommended.

Optional: if your protein does not contain a free cysteine, you must treat your protein with DTT or TCEP to generate a thiol group. DTT or TCEP are used for converting a disulfide bond to two free thiol groups. If DTT is used you must remove free DTT by dialysis or gel filtration before conjugating a dye maleimide to your protein. Following is a sample protocol for generating a free thiol group:
  1. Prepare a fresh solution of 1 M DTT (15.4 mg/100 µL) in distilled water.
  2. Make IgG solution in 20 mM DTT: add 20 µL of DTT stock per ml of IgG solution while mixing. Let stand at room temp for 30 minutes without additional mixing (to minimize reoxidation of cysteines to cystines).
  3. Pass the reduced IgG over a filtration column pre-equilibrated with "Exchange Buffer". Collect 0.25 mL fractions off the column.
  4. Determine the protein concentrations and pool the fractions with the majority of the IgG. This can be done either spectrophotometrically or colorimetrically.
  5. Carry out the conjugation as soon as possible after this step (see Sample Experiment Protocol).
    Note     IgG solutions should be >4 mg/mL for the best results. The antibody should be concentrated if less than 2 mg/mL. Include an extra 10% for losses on the buffer exchange column.
    Note     The reduction can be carried out in almost any buffers from pH 7-7.5, e.g., MES, phosphate or TRIS buffers.
    Note     Steps 3 and 4 can be replaced by dialysis. 

SAMPLE EXPERIMENTAL PROTOCOL

This labeling protocol was developed for the conjugate of Goat anti-mouse IgG with iFluor™ 800 maleimide. You might need further optimization for your particular proteins.
Note     Each protein requires distinct dye/protein ratio, which also depends on the properties of dyes. Over labeling of a protein could detrimentally affects its binding affinity while the protein conjugates of low dye/protein ratio gives reduced sensitivity.


Run conjugation reaction
  1. Use 10:1 molar ratio of Solution B (dye)/Solution A (protein) as the starting point:  Add 5 µL of the dye stock solution (Solution B, assuming the dye stock solution is 10 mM) into the vial of the protein solution (95 µL of Solution A) with effective shaking. The concentration of the protein is ~0.05 mM assuming the protein concentration is 10 mg/mL and the molecular weight of the protein is ~200KD.
    Note     We recommend to use 10:1 molar ratio of Solution B (dye)/Solution A (protein). If it is too less or too high, determine the optimal dye/protein ratio at 5:1, 15:1 and 20:1 respectively.
  2. Continue to rotate or shake the reaction mixture at room temperature for 30-60 minutes. 

Purify the conjugation
The following protocol is an example of dye-protein conjugate purification by using a Sephadex G-25 column.
  1. Prepare Sephadex G-25 column according to the manufacture instruction.
  2. Load the reaction mixture (From "Run conjugation reaction") to the top of the Sephadex G-25 column.
  3. Add PBS (pH 7.2-7.4) as soon as the sample runs just below the top resin surface.
  4. Add more PBS (pH 7.2-7.4) to the desired sample to complete the column purification. Combine the fractions that contain the desired dye-protein conjugate.
    Note     For immediate use, the dye-protein conjugate need be diluted with staining buffer, and aliquoted for multiple uses.
    Note     For longer term storage, dye-protein conjugate solution need be concentrated or freeze dried. 

Calculators

Common stock solution preparation

Table 1. Volume of DMSO needed to reconstitute specific mass of iFluor® 800 maleimide 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 mM61.817 µL309.085 µL618.169 µL3.091 mL6.182 mL
5 mM12.363 µL61.817 µL123.634 µL618.169 µL1.236 mL
10 mM6.182 µL30.908 µL61.817 µL309.085 µL618.169 µL

Molarity calculator

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

Mass (Calculate)Molecular weightVolume (Calculate)Concentration (Calculate)Moles
/=x=

Spectrum

Product family

NameExcitation (nm)Emission (nm)Extinction coefficient (cm -1 M -1)Quantum yieldCorrection Factor (260 nm)Correction Factor (280 nm)
iFluor® 350 maleimide3454502000010.9510.830.23
iFluor® 488 maleimide4915167500010.910.210.11
iFluor® 555 maleimide55757010000010.6410.230.14
iFluor® 647 maleimide65667025000010.2510.030.03
iFluor® 680 maleimide68470122000010.2310.0970.094
iFluor® 700 maleimide69071322000010.2310.090.04
iFluor® 750 maleimide75777927500010.1210.0440.039
iFluor® 790 maleimide78781225000010.1310.10.09
iFluor® 810 maleimide81182225000010.0510.090.15
iFluor® 820 maleimide82285025000010.110.16
iFluor® 860 maleimide85387825000010.10.14
iFluor® 532 maleimide5375609000010.6810.260.16
iFluor® 594 maleimide58760320000010.5310.050.04
iFluor® 405 maleimide4034273700010.9110.480.77
iFluor® 430 maleimide4334984000010.7810.680.3
iFluor® 568 maleimide56858710000010.5710.340.15
iFluor® 633 maleimide64065425000010.2910.0620.044
iFluor® 450 maleimide4515024000010.8210.450.27
iFluor® 460 maleimide468493800001~0.810.980.46
iFluor® 665 maleimide667692110,00010.2210.120.09
iFluor® 546 maleimide54155710000010.6710.250.15
iFluor® 840 maleimide8368792000001-0.20.09
iFluor® 770 maleimide77779725000010.160.090.08
iFluor® 780 maleimide78480825000010.1610.130.12
iFluor® 830 maleimide830867----
iFluor® 514 maleimide5115277500010.8310.2650.116
iFluor® 660 maleimide66367825000010.2610.070.08
iFluor® 670 maleimide67168220000010.5510.030.033
iFluor® 720 maleimide71674024000010.1410.150.13
Show More (20)

Citations

View all 1 citations: Citation Explorer
Nanovesicle delivery to the liver via retinol binding protein and platelet-derived growth factor receptors: how targeting ligands affect biodistribution
Authors: Hsu, Ching-Yun and Chen, Chun-Han and Aljuffali, Ibrahim A and Dai, You-Shan and Fang, Jia-You
Journal: Nanomedicine (2017)

References

View all 18 references: Citation Explorer
A target cell-specific activatable fluorescence probe for in vivo molecular imaging of cancer based on a self-quenched avidin-rhodamine conjugate
Authors: Hama Y, Urano Y, Koyama Y, Kamiya M, Bernardo M, Paik RS, Shin IS, Paik CH, Choyke PL, Kobayashi H.
Journal: Cancer Res (2007): 2791
Fluorescence imaging in vivo: recent advances
Authors: Rao J, Dragulescu-Andrasi A, Yao H.
Journal: Curr Opin Biotechnol (2007): 17
Ex vivo fluorescence imaging of normal and malignant urothelial cells to enhance early diagnosis
Authors: Steenkeste K, Lecart S, Deniset A, Pernot P, Eschwege P, Ferlicot S, Leveque-Fort S, Bri and et R, Fontaine-Aupart MP.
Journal: Photochem Photobiol (2007): 1157
In vivo monitoring the fate of Cy5.5-Tat labeled T lymphocytes by quantitative near-infrared fluorescence imaging during acute brain inflammation in a rat model of experimental autoimmune encephalomyelitis
Authors: Berger C, Gremlich HU, Schmidt P, Cannet C, Kneuer R, Hiest and P, Rausch M, Rudin M.
Journal: J Immunol Methods (2007): 65
A protocol for imaging alternative splicing regulation in vivo using fluorescence reporters in transgenic mice
Authors: Bonano VI, Oltean S, Garcia-Blanco MA.
Journal: Nat Protoc (2007): 2166
Page updated on October 10, 2024

Ordering information

Price
Unit size
Catalog Number1378
Quantity
Add to cart

Additional ordering information

Telephone1-800-990-8053
Fax1-800-609-2943
Emailsales@aatbio.com
InternationalSee distributors
Bulk requestInquire
Custom sizeInquire
Technical SupportContact us
Purchase orderSend to sales@aatbio.com
ShippingStandard overnight for United States, inquire for international
Request quotation

Physical properties

Molecular weight

1617.68

Solvent

DMSO

Spectral properties

Correction Factor (260 nm)

0.03

Correction Factor (280 nm)

0.08

Extinction coefficient (cm -1 M -1)

2500001

Excitation (nm)

801

Emission (nm)

820

Quantum yield

0.111

Storage, safety and handling

H-phraseH303, H313, H333
Hazard symbolXN
Intended useResearch Use Only (RUO)
R-phraseR20, R21, R22

Storage

Freeze (< -15 °C); Minimize light exposure
UNSPSC12171501