Scattering angle resolved optical coherence tomography measures morphological changes in colonies.

SIGNIFICANCE

An unmet need is recognized for early detection and diagnosis of neurological diseases. Many psychological markers emerge years after disease onset. Mitochondrial dysfunction and corresponding neurodegeneration occur before onset of large-scale cell and tissue pathology. Early detection of subcellular morphology changes could serve as a beacon for early detection of neurological diseases. This study is on bacterial colonies, , which are similar in size to mitochondria.

AIM

This study investigates whether morphological changes can be detected in using scattering angle resolved optical coherence tomography (SAR-OCT).

APPROACH

The SAR-OCT was applied to detect scattering angle distribution changes in The rod-to-coccus shape transition of the bacteria was imaged, and the backscattering angle was analyzed by recording the distribution of the ratio of low- to medium angle scattering (L/M ratio). orientation at different locations in colonies was analytically modeled and compared with SAR-OCT results.

RESULTS

Significant differences in the distribution of backscattering angle were observed in transitioning from rod-to-coccus shapes. In , the -parameter of the Burr distribution of the SAR-OCT-derived L/M ratio was significantly smaller in coccus compared with rod-shaped bacteria. SAR-OCT-derived L/M ratio varied with bacterial position in the colony and is consistent with predicted orientations from previous studies.

CONCLUSIONS

Study results support the potential of utilizing SAR-OCT to detect bacterial morphological changes.