All-digital histopathology by infrared-optical hybrid microscopy

Martin Schnell, Shachi Mittal, Kianoush Falahkheirkhah, Anirudh Mittal, Kevin Yeh, Seth Kenkel, Andre Kajdacsy-Balla, P. Scott Carney, Rohit Bhargava

Research output: Contribution to journalArticlepeer-review


Optical microscopy for biomedical samples requires expertise in staining to visualize structure and composition. Midinfrared (mid-IR) spectroscopic imaging offers label-free molecular recording and virtual staining by probing fundamental vibrational modes of molecular components. This quantitative signal can be combined with machine learning to enable microscopy in diverse fields from cancer diagnoses to forensics. However, absorption of IR light by common optical imaging components makes mid-IR light incompatible with modern optical microscopy and almost all biomedical research and clinical workflows. Here we conceptualize an IR-optical hybrid (IR-OH) approach that sensitively measures molecular composition based on an optical microscope with widefield interferometric detection of absorption-induced sample expansion. We demonstrate that IR-OH exceeds state-of-the-art IR microscopy in coverage (10-fold), spatial resolution (fourfold), and spectral consistency (by mitigating the effects of scattering). The combined impact of these advances allows full slide infrared absorption images of unstained breast tissue sections on a visible microscope platform.We further show that automated histopathologic segmentation and generation of computationally stained (stainless) images is possible, resolving morphological features in both color and spatial detail comparable to current pathology protocols but without stains or human interpretation. IR-OH is compatible with clinical and research pathology practice and could make for a cost-effective alternative to conventional stain-based protocols for stainless, all-digital pathology.

Original languageEnglish (US)
Article number201912400
Pages (from-to)3388-3396
Number of pages9
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number7
StatePublished - Feb 18 2020


  • Breast cancer
  • Imaging
  • Infrared spectroscopy
  • Pathology
  • Quantum cascade laser

ASJC Scopus subject areas

  • General


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