Single-Cell Photoacoustic Microrheology.

Rheological properties, such as elasticity and viscosity, are fundamental biomechanical parameters that are related to the function and pathological status of cells and tissues. In this paper, an innovative photoacoustic microrheology (PAMR), which utilized the time and phase characteristics of photoacoustic (PA) response, was proposed to extract elastic modulus and viscosity. The feasibility and accuracy of the method were validated by tissue-mimicking agar-gelatin phantoms with various viscoelasticity values. PAMR realized single cell elasticity and viscosity mappings on the adipocyte and myocyte with micrometer scale. In clinical samples, normal blood cells and iron deficiency anemia cells were successfully distinguished due to their various rheological properties. This method expands the scope of conventional PA imaging and opens new possibilities for developing microrheological technology, prefiguring great clinical potential for interrogating mechanocellular properties.