Indo-1, pentasodium salt

Calcium measurements are critical for numerous biological investigations. Fluorescent probes that show spectral responses upon binding to Ca2+ have enabled researchers to investigate changes in intracellular free Ca2+ concentrations by using fluorescence microscopy, flow cytometry, fluorescence spectroscopy, and fluorescence microplate readers. This cell-impermeant Indo-1 pentasodium salt is a UV light excitable, emission ratioable Ca2+ indicator. Upon binding to Ca2+, the emission maximum of Indo-1 shifts from 480 nm to 400 nm. Indo-1 is preferred for flow cytometry, in which it is more practical to use a single laser for excitation, such as the 351-364 nm spectral lines of the argon-ion laser.

The fluorescence emission spectra of Indo-1 measured in solutions containing 0 to 39 µM of free calcium ions.

Protocol

SDS

COA

Catalog	Size	Price	Quantity
21044	1 mg	Price

Calculators

Common stock solution preparation

Table 1. Volume of Water needed to reconstitute specific mass of Indo-1, pentasodium salt to given concentration. Note that volume is only for preparing stock solution. Refer to sample experimental protocol for appropriate experimental/physiological buffers.

	0.1 mg	0.5 mg	1 mg	5 mg	10 mg
1 mM	131.662 µL	658.311 µL	1.317 mL	6.583 mL	13.166 mL
5 mM	26.332 µL	131.662 µL	263.324 µL	1.317 mL	2.633 mL
10 mM	13.166 µL	65.831 µL	131.662 µL	658.311 µL	1.317 mL

Molarity calculator

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

Mass (Calculate)		Molecular weight		Volume (Calculate)		Concentration (Calculate)		Moles
mg	÷	759.52 g/mol	=	mL	x	mM	=	mmol

Citations

View all 4 citations: Citation Explorer

Nifedipine stimulates proliferation and migration of different breast cancer cells by distinct pathways

Authors:

Zhao, Tao and Guo, Dongqing and Gu, Yuchun and Ling, Yang

Journal:

Molecular Medicine Reports (2017): 2259--2263

Inhibition of pyruvate kinase M2 by reactive oxygen species contributes to the development of pulmonary arterial hypertension

Authors:

Guo, Dongqing and Gu, Junzhong and Jiang, Hui and Ahmed, Asif and Zhang, Zhiren and Gu, Yuchun

Journal:

Journal of molecular and cellular cardiology (2016): 179--187

Nifedipine promotes the proliferation and migration of breast cancer cells

Authors:

Guo, Dong-Qing and Zhang, Hao and Tan, Sheng-Jiang and Gu, Yu-Chun

Journal:

PloS one (2014): e113649

Bioanalytics/Illumination: Just-right light-Inherently adaptive for application-specific needs

Authors:

JOHNSON, IAIN

References

View all 84 references: Citation Explorer

Measurement of [Ca2+] in cell suspensions using indo-1

Authors:

Nelemans A., undefined

Journal:

Methods Mol Biol (2006): 47

A flow cytometric comparison of Indo-1 to fluo-3 and Fura Red excited with low power lasers for detecting Ca(2+) flux

Authors:

Bailey S, Macardle PJ.

Journal:

J Immunol Methods (2006): 220

Ratiometric intracellular calcium imaging in the isolated beating rat heart using indo-1 fluorescence

Authors:

Eerbeek O, Mik EG, Zuurbier CJ, van 't Loo M, Donkersloot C, Ince C.

Journal:

J Appl Physiol (2004): 2042

Negative inotropic effects of angiotensin II, endothelin-1 and phenylephrine in indo-1 loaded adult mouse ventricular myocytes

Authors:

Sakurai K, Norota I, Tanaka H, Kubota I, Tomoike H, Endo M.

Journal:

Life Sci (2002): 1173

Usefulness of the analytic method of intracellular calcium and the problems--aequorin and indo-1 signal

Authors:

Endoh M., undefined

Journal:

Nippon Yakurigaku Zasshi (2000): 361

Physical properties

Dissociation constant (K_d, nM)	230
Molecular weight	759.52
Solvent	Water

Spectral properties

Extinction coefficient (cm ^-1 M ^-1)	33000
Excitation (nm)	330
Emission (nm)	404

Storage, safety and handling

H-phrase	H303, H313, H333
Hazard symbol	XN
Intended use	Research Use Only (RUO)
R-phrase	R20, R21, R22
Storage	Freeze (< -15 °C); Minimize light exposure
UNSPSC	12352200

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Page updated on October 12, 2025