Researchers at Oregon State University (OSU) say they have created a nanomedicine technique for cancer that can help doctors know which tissue to remove while simultaneously killing any malignant cells that can't be cut out. The scientists from the OSU/Oregon Health & Science University (OHSU) College of Pharmacy and OSU College of Veterinary Medicine published their study (“A Tumor-Activatable Theranostic Nanomedicine Platform for NIR Fluorescence-Guided Surgery and Combinatorial Phototherapy”) in Theranostics.
“Fluorescence image-guided surgery combined with intraoperative therapeutic modalities has great potential for intraoperative detection of oncologic targets and eradication of unresectable cancer residues. Therefore, we have developed an activatable theranostic nanoplatform that can be used concurrently for two purposes: (1) tumor delineation with real-time near infrared (NIR) fluorescence signal during surgery, and (2) intraoperative targeted treatment to further eliminate unresected disease sites by non-toxic phototherapy,” write the investigators.
Nanoparticles tightly loaded with a dye compound are injected intravenously or into the peritoneum. When they reach the tumor site, the tumor's intracellular environment effectively flips the switch on the compound's fluorescence. That enables detection by a NIR imaging system that helps surgeons know in real time what needs to be removed. Any glowing areas that can't be cut out are given phototherapy, I.e., irradiated with a near-infrared laser, which causes the nanoparticles to heat up and kill the residual cancer cells.
The system consists of silicon naphthalocyanine (SiNc) densely packed in biodegradable poly(ethylene glycol)-b-poly(?-caprolactone) (PEG-PCL) nanoparticles. Because the SiNc is engineered to be nonfluorescent initially—until the tumor activates the fluorescence by loosening the packing—it doesn't cause any noncancerous tissue to glow.
Olena Taratula, Ph.D., and Oleh Taratula, Ph.D., of the department of pharmaceutical sciences, and their collaborators studied the platform in vitro and in two different mouse models, including one that mimicked ovarian intraperitoneal metastasis. The mice were operated upon using real-time imaging, which showed that the new nanoparticles are compatible with a standard, FDA-approved imaging system. The efficacy of the phototherapy was also demonstrated in vivo.
“The nanoplatform system is quite simple but quite effective,” Dr. Olena Taratula said.
Additional testing will take place on rats and dogs already scheduled for cancer surgeries at the College of Veterinary Medicine.