Near-infrared voltage-sensitive fluorescent dyes optimized for optical mapping in blood-perfused myocardium.
BACKGROUND
Styryl voltage-sensitive dyes (e.g., di-4-ANEPPS) have been used successfully for optical mapping in cardiac cells and tissues. However, their utility for probing electrical activity deep inside the myocardial wall and in blood-perfused myocardium has been limited because of light scattering and high absorption by endogenous chromophores and hemoglobin at blue-green excitation wavelengths.


OBJECTIVE
The purpose of this study was to characterize two new styryl dyes--di-4-ANBDQPQ (JPW-6003) and di-4-ANBDQBS (JPW-6033)--optimized for blood-perfused tissue and intramural optical mapping.


METHODS
Voltage-dependent spectra were recorded in a model lipid bilayer. Optical mapping experiments were conducted in four species (mouse, rat, guinea pig, and pig). Hearts were Langendorff perfused using Tyrode's solution and blood (pig). Dyes were loaded via bolus injection into perfusate. Transillumination experiments were conducted in isolated coronary-perfused pig right ventricular wall preparations.


RESULTS
The optimal excitation wavelength in cardiac tissues (650 nm) was >70 nm beyond the absorption maximum of hemoglobin. Voltage sensitivity of both dyes was approximately 10% to 20%. Signal decay half-life due to dye internalization was 80 to 210 minutes, which is 5 to 7 times slower than for di-4-ANEPPS. In transillumination mode, DeltaF/F was as high as 20%. In blood-perfused tissues, DeltaF/F reached 5.5% (1.8 times higher than for di-4-ANEPPS).


CONCLUSIONS
We have synthesized and characterized two new near-infrared dyes with excitation/emission wavelengths shifted >100 nm to the red. They provide both high voltage sensitivity and 5 to 7 times slower internalization rate compared to conventional dyes. The dyes are optimized for deeper tissue probing and optical mapping of blood-perfused tissue, but they also can be used for conventional applications.
Matiukas
Arvydas
A
Department of Pharmacology, State University of New York, Upstate Medical University, Syracuse, New York 13210, USA.
Mitrea
Bogdan G
BG
Qin
Maochun
M
Pertsov
Arkady M
AM
Shvedko
Alexander G
AG
Warren
Mark D
MD
Zaitsev
Alexey V
AV
Wuskell
Joseph P
JP
Wei
Mei-de
MD
Watras
James
J
Loew
Leslie M
LM
D000200:Action Potentials; D018780:Body Surface Potential Mapping / Q000295:instrumentation* / Q000379:methods; D004594:Electrophysiology; D005456:Fluorescent Dyes; D006801:Humans; D008564:Membrane Potentials; D008955:Models, Cardiovascular; D015425:Myocardial Reperfusion; D009206:Myocardium; D055095:Optics and Photonics / Q000295:instrumentation*; D013050:Spectrometry, Fluorescence; D019265:Spectroscopy, Near-Infrared
D005456:Fluorescent Dyes