Fast NIR Probes for Optical Electrophysiology
imaging of myocardial tissue is traditionally done by using either branch
electrodes, or high voltage sensitive dye. Both of these mapping procedures have
significant drawbacks. Using branch electrodes to map the myocardial tissue is
problematic because several needles have to be inserted into the heart, causing
damage to heart muscle. Furthermore this method yields inconsistent measurements
due to the size and displacement of the needles from one another. Current high
voltage sensitive dye is problematic because it cannot penetrate thick tissue at
depth. Furthermore the excitation wavelength of the current dyes is in the same
range wavelength that blood and tissue typically absorb (450-550 nanometers).
This results in low image quality even with a very high light intensity.
new probe is in the styryl class of dyes, developed with researchers at the
University of Connecticut, but can be used to image thick tissue at a greater
depth than current styryl-class dyes. The new dye fluoresces at a wavelength
range of 700 to 900 nanometers, which significantly reduces interference from
biological tissue so a clearer image can be obtained, is able to penetrate
deeper into thick tissue than currently used dyes (up to 20 mm), can remain in
tissue for 2-4 hours even if it is blood perfused, and have fast response times
(responds to membrane potential changes in less than 1 millisecond).