Cancer is a global public health challenge and one of the leading causes of death worldwide. Treatment outcomes significantly improve with early detection and intervention, prompting continuous advancements in cancer detection methods. Due to its ability for label free chemical imaging, Mid-IR has been used by multiple groups to identify cancerous tissues and cells [1] and to supplant current chemical staining-based pathology approaches. Our goal is to use IR to distinguish between healthy, cancerous, and metastasizing cells in tumor-on-a-chip systems. While FTIR imaging has been highly successful with tissue sections [2], applications in large, water-filled channels demands a different approach. We have developed a mid-IR photothermal (MIP) spectroscopy setup specifically tailored for organ-on-a-chip spectroscopy. This instrument allows for sensitive absorption imaging in the presence of several millimeters of water and does not need further adaptation for mid-IR spectroscopy, aside from requiring an IR-transparent sample carrier. Here, we present our findings on utilizing clustering algorithms and infrared spectroscopy to differentiate between cancerous and healthy cells. Additionally, we compare spectra obtained through conventional FTIR microscopy with those acquired using our MIP setup. As a final step, we are able to analyze the chemical composition of the individual cells through imaging. ___ [1] Liu Dong et al., ‘Evaluation of Fourier Transform Infrared (FTIR) Spectroscopy with Multivariate Analysis as a Novel Diagnostic Tool for Lymph Node Metastasis in Gastric Cancer’, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 289 (2023) 122209. [2] Hersh K. Bhargava et al., ‘Computationally Derived Image Signature of Stromal Morphology Is Prognostic of Prostate Cancer Recurrence Following Prostatectomy in African American Patients’, Clinical Cancer Research 26, no. 8 (2020): 1915–23