Cancer Detection in Human Tissue Samples Using a Fiber-Tip pH Probe

Intraoperative detection of tumorous tissue is an important unresolved issue for cancer surgery. Difficulty in differentiating between tissue types commonly results in the requirement for additional surgeries to excise unremoved cancer tissue or alternatively in the removal of excess amounts of healthy tissue. Although pathologic methods exist to determine tissue type during surgery, these methods can compromise postoperative pathology, have a lag of minutes to hours before the surgeon receives the results of the tissue analysis, and are restricted to excised tissue. In this work, we report the development of an optical fiber probe that could potentially find use as an aid for margin detection during surgery. A fluorophore-doped polymer coating is deposited on the tip of an optical fiber, which can then be used to record the pH by monitoring the emission spectra from this dye. By measuring the tissue pH and comparing with the values from regular tissue, the tissue type can be determined quickly and accurately. The use of a novel lift-and-measure technique allows for these measurements to be performed without influence from the inherent autofluorescence that commonly affects fluorescence-based measurements on biological samples. The probe developed here shows strong potential for use during surgery, as the probe design can be readily adapted to a low-cost portable configuration, which could find use in the operating theater. Use of this probe in surgery either on excised or in vivo tissue has the potential to improve success rates for complete removal of cancers. Cancer Res; 76(23); 6795-801. ©2016 AACR.