Near-infrared voltage-sensitive fluorescent dyes optimized for optical mapping in blood-perfused myocardium

Abstract

Background-Styryl voltage-sensitive dyes (e.g. di-4-ANEPPS) have been successfully used 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.

Electrotonic coupling of excitable and nonexcitable cells in the heart revealed by optogenetics

“…2A). To assess VSFP2.3 signal kinetics, hearts were additionally (and cell-indiscriminately) stained by coronary perfusion of a voltage-sensitive fluorescent dye (di-4-ANBDQPQ) (22). As in a previous report (23), VSFP2.3 reliably captures cardiac AP presence.…”

“…Hearts were excitation-contraction uncoupled with 10 μM (±)-blebbistatin (Abcam). Eight αMHC;VSFP2.3 +;+ hearts (nonsurgery controls) were additionally stained with a voltage-sensitive fluorescent dye [di-4-ANBDQPQ; University of Connecticut Health Center (22)]. For simultaneous dual-wavelength emission imaging, fluorescence at each wavelength was collected at 511 frames per second from a 300 × 600-μm area onto one-half of a 128 × 128-pixel electron multiplying charge-coupled device camera (Cascade:128+; Photometrics).…”

A technical review of optical mapping of intracellular calcium within myocardial tissue

“…Such probes are advantageous for imaging deeper within the myocardium (Ͼ4 mm) due to reduced absorption and scattering by endogenous chromophores within the excitation and emission bands of the probes (110). Another advantage is that near-infrared probes enable optical mapping of blood-perfused myocardium (62), avoiding the high absorbance of blood in the shorter blue-green band. PGH-I has far red-shifted excitation and emission spectra and provides large signal amplitudes, but it can be somewhat difficult to load in myocardial tissue.…”

Single molecule quantum-confined Stark effect measurements of semiconductor nanoparticles at room temperature

“…Could we expect high enough sensitivity (Δλ/λ) in hydrated environment (ε r = 80) as compared to conventional voltage-sensitive dyes (which exhibit up to ΔI/I ∼ 20% for ΔV = 100 mV)? 31 Affirmative answers to these questions could imply that such NPs could act as local voltage sensors on the nanoscale (displaying changes in fluorescence quantum yield, fluorescence lifetime, and/or peak emission wavelength in response to the local electric field).…”