Laser speckle particle sizer (SPARSE) for characterizing cellular structures in tissue

Particle sizing of cellular structures may have significant diagnostic utility. We introduce a laser Speckle PARticle SizEr (SPARSE) that harnesses the spatio-temporal analysis of polarized speckle to estimate scattering particle sizes in opaque biofluids and tissues. SPARSE measurements significantly correlate with dynamic light scattering (DLS) in polybead suspensions (R2=0.91, p<.0001) and milk samples (R2=0.93, p<.0001). Similarly, in whole blood samples of increasing tonicities, SPARSE tracks RBC shrinkage in concordance with DLS (R2=0.84, p<.0001). Moreover, SPARSE maps of breast carcinoma reveal distinct sizes for adipose, fibrous, and epithelial compartments. These findings highlight the diagnostic potential of SPARSE in multiple conditions.