Infrared spectroscopic laser scanning confocal microscopy for whole-slide chemical imaging

Chemical imaging, especially mid-infrared spectroscopic microscopy, enables label-free biomedical analyses while achieving expansivemolecular sensitivity. However, its slow speed and poor image quality impede widespread adoption. We present a microscope that provides high-throughput recording, low noise, and high spatial resolution where the bottom-up design of its optical train facilitates dual-axis galvo laser scanning of a diffraction-limited focal point over large areas using custom, compound, infinity-corrected refractive objectives. We demonstrate whole-slide, speckle-free imaging in similar to 3min per discrete wavelength at 10x magnification (2 mu m/pixel) and high-resolution capability with its 20x counterpart (1 mu m/pixel), both offering spatial quality at theoretical limits while maintaining high signal-to-noise ratios (>100:1). The data quality enables applications of modern machine learning and capabilities not previously feasible - 3D reconstructions using serial sections, comprehensive assessments of whole model organisms, and histological assessments ofdisease in timecomparable toclinicalworkflows. Distinct from conventional approaches that focus on morphological investigations or immunostaining techniques, this development makes label-free imaging of minimally processed tissue practical.

Automated summary

Chemical imaging, especially mid-infrared spectroscopic microscopy, allows label-free biomedical analysis with high molecular sensitivity. However, its slow speed and poor image quality hinder its widespread adoption. A new microscope design overcomes these limitations by providing high-throughput recording, low noise, and high spatial resolution, enabling speckle-free, high-resolution imaging at theoretical limits.