The development of a far red to near infrared fluorescent probe for use in optical imaging.

摘要

New techniques for biological optical imaging are of great interest for the detection and visualization of processes and disease in both clinical and research areas. One major advancement has been the use of far red and near infrared (NIR) light, as it has the ability to penetrate tissues deeper than other parts of the spectrum which are readily scatter and absorbed by the surroundings. In order to improve the signal to noise ratio and resolution of optical images, contrast agents are used. Fluorescent markers can be modified to attach to specific molecular targets, creating small molecular probes. These targets can be disease sites, or biological molecules which play a major role in processes such as tumor growth. It was our goal to create a new novel fluorescent probe, consisting of a cyanine based far red to NIR marker, and an n-hydroxysuccinimide (NHS) derivative to act as a linker, which could then bind with biological species containing primary amides such as proteins and antibodies, in this model system bovine serum albumin (BSA). The dye, a modified pentamethine carbocyanine, was synthesized according to Shao, et al., (Bioconjugate Chem 2008) and was chosen for its previous use for in vivo visualization and preferred spectral properties, as well as its ability to incorporate different functionalities. The linker was an azide functionalized NHS derivative chosen for its crosslinking ability with species containing primary amides. Azide and alkyne functionality were of great interest due to their reactivity in [2+3] dipolar cycloaddition click type reactions, which was used to attach an azide on the NHS derivative and an alkyne on the dye. This species was then bound to protein, BSA, successfully through this NHS moiety.