Preliminary evaluation of a nanotechnology-based approach for the more effective diagnosis of colon cancers

Aim: The goal of this research was to develop and preliminarily test a novel technology and instrumentation that could help to significantly increase the diagnostic yield of current colon cancer screening procedures. This technology is based on a combined fluorescence optical coherence tomography (OCT) imaging, and topical delivery of a cancer-targeting agent. Materials & methods: Gold colloid-adsorbed poly(epsilon-caprolactone) microparticles were labeled with a near-infrared dye, and functionalized with argentine glycine aspartic acid (RGD peptide) to effectively target cancer tissue, and enhance fluorescence-imaging contrast. The RGD peptide recognizes the alpha,beta(3)-integrin receptor, which is overexpressed by epithelial cancer cells. OCT was used under fluorescence guidance to visualize tissue morphology and, thus, to serve as a confirmatory tool for cancer presence. Results: A preliminary testing of this technology on human colon cancer cell lines, a mouse model of colon cancer, as well as human colon tissue specimens, was performed. Strong binding of microparticles to cancer cells and no binding to cells that do not significantly express integrins, such as mouse fibroblasts, was observed. Preferential binding to cancer tissue was also observed. Strong fluorescence signals were obtained from cancer tissue, owing to the efficient binding of the contrast agent. OCT imaging was capable of revealing clear differences between normal and cancer tissue. Conclusion: A dual-modality imaging approach combined with topical delivery of a cancer-targeting contrast agent has been preliminarily tested for colon cancer diagnosis. Preferential binding of the contrast agent to cancer tissue allowed the cancer-suspicious locations to be highlighted and, thus, guided OCT imaging to visualize tissue morphology and determine tissue type. If successful, this multimodal approach might help to increase the sensitivity and the specificity of current colon cancer-screening procedures in the future.