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Updated: Jan 15, 2026
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Published on: July 17, 2012
Sprayable pH-sensitive near-infrared fluorophore for rapid, bright, specific, and safe visualization of human thyroid
Sunidhi Jaiswal1, Atsushi Yamashita2, Sohee Lee3
1Department of Surgery, University of California San Diego, La Jolla, CA; Department of Surgery, VA San Diego Healthcare System, La Jolla, CA.
Background:
Surgery is the primary treatment for thyroid cancer. However, incomplete resection of thyroid cancer can result in local, regional, and distant recurrences that are life threatening. We hypothesized that a topically applied, pH-sensitive near-infrared fluorophore in spray form (PH10) could offer rapid labeling of thyroid tumors, enabling better visualizion of the tumor and its margins.
Methods:
Cellar uptake inhibition and cytotoxicity studies using PH10 were performed on TPC-1 papillary and TT medullary thyroid cancer cells. Subcutaneous or orthotopic tumors were established by injecting TPC-1 cells in the flanks or thyroid glands of nude mice, respectively, and sprayed with PH10. Fluorescence of the tumor was compared to surrounding tissues. Tumors were harvested for pathologic analysis.
Results:
The organic anion transporter peptide mediated uptake of PH10 in TPC-1 and TT cells was determined. PH10 exhibited an IC50 value of 13.18 and 17.28 μM in TPC-1 and TT cells, respectively. Both subcutaneous and orthotopic tumors displayed strong near-infrared fluorescence upon spraying PH10 at a concentration of 10 μM on the tumor sites, within 1 minute, contrasting with surrounding tissues. The effective PH10 dose for tumor visualization was well below the IC50. The average tumor to background ratios were 5.5 (±1.47) for subcutaneous tumors (n = 5) and 9.4 (±2.59) for orthotopic tumors (n = 5). Hematoxylin and eosin staining confirmed the tumor characteristics.
Conclusion:
The pH-sensitive near-infrared fluorophore PH10 brightly, rapidly, specifically, and safely labeled thyroid cancer in mouse models by spraying, demonstrating future clinical promise as a useful agent for improved visualization of thyroid cancer.
Insights
A novel pH-sensitive near-infrared fluorophore, PH10, effectively labeled thyroid cancer in mice. This sprayable agent offers rapid and specific tumor visualization, potentially improving surgical outcomes for thyroid cancer patients.
Area of Science:
- Oncology
- Medical Imaging
- Biotechnology
Background:
- Surgery is the primary treatment for thyroid cancer, but incomplete resection leads to recurrence.
- Accurate tumor margin visualization is crucial for successful thyroid cancer surgery.
- A pH-sensitive near-infrared fluorophore (PH10) was developed for topical application.
Purpose of the Study:
- To evaluate the efficacy of PH10 in labeling thyroid tumors in preclinical models.
- To assess the safety and specificity of PH10 for tumor visualization.
- To determine the potential of PH10 as an adjunct for thyroid cancer surgery.
Main Methods:
- PH10 uptake and cytotoxicity were studied in thyroid cancer cell lines (TPC-1 and TT).
- Subcutaneous and orthotopic thyroid tumors were established in nude mice.
- PH10 was topically sprayed onto tumors, and fluorescence was quantified and compared to surrounding tissues.
Main Results:
- PH10 demonstrated effective uptake and was non-toxic at effective concentrations.
- Spraying PH10 resulted in rapid and strong near-infrared fluorescence of both subcutaneous and orthotopic tumors.
- High tumor-to-background ratios (5.5 and 9.4) indicated specific tumor labeling with minimal background signal.
Conclusions:
- PH10 brightly, rapidly, and specifically labeled thyroid cancer in mouse models.
- The sprayable formulation of PH10 demonstrated safety and efficacy in preclinical studies.
- PH10 shows significant clinical promise for enhancing thyroid cancer visualization during surgery.
