Functional probe for annulus fibrosus-targeted intervertebral disc degeneration imaging.

Intervertebral disc degeneration (IDD) is closely associated with low back pain. Typically nonsurgical treatment of IDD is the most effective when detected early. As such, establishing reliable imaging methods for the early diagnosis of disc degeneration is critical. The cellular and tissue localization of a facile functional fluorescent probe, HYK52, that labels disc annulus fibrosus is reported. HYK52 was synthesized with high yield and purity via a two-step chemical reaction. Rabbit disc cell studies and ex vivo tissue staining images indicated intracellular localization and intervertebral disc (IVD) tissue binding of HYK52 with negligible cytotoxicity. Moreover, HYK52 is purposefully designed with a functional terminal carboxyl group to allow for coupling with various signaling molecules for multimodal imaging applications. These results suggest that this IVD-targeted probe may have great potential in early diagnosis of IDD.