Mouse models are essential tools for understanding cancer growth and accelerating the development of therapeutic and diagnostic technologies. Xenografts, generated by implanting tumor cells directly into mice through injection, are frequently used to study cancer biology and therapeutics. In these models, assessment of tumor growth and development is necessary to support the study of disease progression and model validation. Unfortunately, such measurements often require sacrificing the animal to create organ explants or tissue cultures, resulting in increased animal use and hampering longitudinal measurements of individual tumors. A tool enabling in vivo tumor monitoring for xenograft models could improve the efficiency of these animal models and provide more robust growth measurements through true longitudinal measurement.

One method of optical tumor assessment involves tagging biomolecules of interest with fluorescent species to enable detection with minimally invasive fluorescence imaging, implemented endoscopically or laparoscopically. However, utilizing fluorescence imaging in vivo in murine models poses challenges due to both tortuous anatomy and small gastrointestinal lumen caliber.

This work reports a miniature fluorescence imaging probe equipped with a multiband filter and biopsy device to image and sample fluorescently-tagged, xenografted tumors as they develop in mouse models. We present the design and characterization of the device and report measurements of the modulation transfer function and ex vivo imaging performance, demonstrating its promise as a valuable research tool to advance cancer research in xenograft models, enabling the development of imaging biomarkers for cancer detection in a clinical setting without the need for exogenous contrast.