Comparative analysis of photoacoustic imaging of immune cells in the context of drug treatment

Valproic acid (VPA) is an epigenetic regulator used in the treatment of epilepsy and other neurological disorders for the past 50 years. The direct impact of VPA on cells of the immune system has only been explored recently. Immune cells have been relatively less studied in the context of photoacoustic tomography imaging, which has been used in different biological systems with many different applications in biomedical investigations. Therefore, we aimed to perform a comparative analysis of photoacoustic imaging of immune cells in the context of VPA treatment. Four different doses of VPA (1 mM, 2.5 mM, 5 mM, and 7.5 mM) were applied to in vitro models established with human EoL-1 eosinophilic cell lines and human Jurkat T lymphocyte cell lines. Cell viability was assessed by a trypan blue exclusion test. The changes in morphology caused by VPA were examined with a photoacoustic tomography system. Photoacoustic signals measured from the VPA in different immune cells showed similar results obtained from light microscopy and cell viability. Photoacoustic imaging is promising for identifying and distinguishing different cell types and detecting changes at the cellular level.