Prototype Nerve-Specific Near-Infrared Fluorophores

Nerve preservation is an important issue during most surgery because accidental transection or injury results in significant morbidity, including numbness, pain, weakness, or paralysis. Currently, nerves are still identified only by gross appearance and anatomical location during surgery, without intraoperative image guidance. Near-infrared (NIR) fluorescent light, in the wavelength range of 650-900 nm, has the potential to provide high-resolution, high-sensitivity, and real-time avoidance of nerve damage, but only if nerve-specific NIR fluorophores can be developed. In this study, we evaluated a series of Oxazine derivatives to highlight various peripheral nerve structures in small and large animals. Among the targeted fluorophores, Oxazine 4 has peak emission near into the NIR, which provided nerve-targeted signal in the brachial plexus and sciatic nerve for up to 12 h after a single intravenous injection. In addition, recurrent laryngeal nerves were successfully identified and highlighted in real time in swine, which could be preserved during the course of thyroid resection. Although optical properties of these agents are not yet optimal, chemical structure analysis provides a basis for improving these prototype nerve-specific NIR fluorophores even further

Pancreas-Targeted NIR Fluorophores for Dual-Channel Image-Guided Abdominal Surgery

Objective: Pancreas-related complications are some of the most serious ones in abdominal surgery. The goal of this study was to develop and validate novel near-infrared (NIR) fluorophores that would enable real-time pancreas imaging to avoid the intraoperative pancreatic injury. Design: After initial screening of a large NIR fluorophore library, the performance of 3 selected pancreas-targeted 700 nm NIR fluorophores, T700-H, T700-F, and MB, were quantified in mice, rats, and pigs. Dose ranging using 25 and 100 nmol, and 2.5 μmol of T700-F, and its imaging kinetics over a 4 h period were tested in each species. Three different 800 nm NIR fluorophores were employed for dual-channel FLARE™ imaging in pigs: 2 μmol of ZW800-1 for vessels and kidney, 1 μmol of ZW800-3C for lymph nodes, and 2 μmol of ESNF31 for adrenal glands. Results: T700-F demonstrated the highest signal to background ratio (SBR), with peak SBR at 4 h postinjection in mice. In pigs, T700-F produced an SBR ≥ 2 against muscle, spleen, and lymph nodes for up to 8 h after a single intravenous injection. The combination of T700-F with each 800 nm NIR fluorophore provided simultaneous dual-channel intraoperative imaging of pancreas with surrounding organs in real time. Conclusion: Pancreas-targeted NIR fluorophores combined with the FLARE dual-channel imaging system enable the real-time intraoperative pancreas imaging which helps surgeons perform safer and more curative abdominal surgeries

Near-Infrared Fluorescence Imaging for Noninvasive Trafficking of Scaffold Degradation

Biodegradable scaffolds could revolutionize tissue engineering and regenerative medicine; however, in vivo matrix degradation and tissue ingrowth processes are not fully understood. Currently a large number of samples and animals are required to track biodegradation of implanted scaffolds, and such nonconsecutive single-time-point information from various batches result in inaccurate conclusions. To overcome this limitation, we developed functional biodegradable scaffolds by employing invisible near-infrared fluorescence and followed their degradation behaviors in vitro and in vivo. Using optical fluorescence imaging, the degradation could be quantified in real-time, while tissue ingrowth was tracked by measuring vascularization using magnetic resonance imaging in the same animal over a month. Moreover, we optimized the in vitro process of enzyme-based biodegradation to predict implanted scaffold behaviors in vivo, which was closely related to the site of inoculation. This combined multimodal imaging will benefit tissue engineers by saving time, reducing animal numbers, and offering more accurate conclusions

Endocrine-specific NIR fluorophores for adrenal gland targeting

International audienc

Near-Infrared Illumination of Native Tissues for Image-Guided Surgery

Our initial efforts to prepare tissue-specific near-infrared (NIR) fluorescent compounds generated successful correlation between physicochemical properties and global uptake in major organs after systemic circulation and biodistribution. Herein, we focus on the effects on biodistribution based on modulating electronic influencing moieties from donating to withdrawing moieties at both the heterocyclic site and through <i>meso</i>-substitution of pentamethine cyanine fluorophores. These selected modifications harnessed innate biodistribution pathways through the structure-inherent targeting, resulting in effective imaging of the adrenal glands, pituitary gland, lymph nodes, pancreas, and thyroid and salivary glands. These native-tissue contrast agents will arm surgeons with a powerful and versatile arsenal for intraoperative NIR imaging in real time