The need for optoacoustic microscopy

Optoacoustic (photoacoustic) microscopy resolves optical absorption in cells and tissues, thus offering a complementary contrast mechanism to optical microscopy. Yet, the marked advances in optical microscopy techniques and their widespread use beg the question of the particular need and utility of an additional microscopy modality that resolves optical absorption. Recent advances that point to advantageous features and uses of optoacoustic microscopy in biological and clinical interrogation are presented. How these advances can be manifested as part of hybrid implementations using optical, optoacoustic, and possibly other forms of microscopy to enhance the ability of the microscopic interrogation is reviewed. Further examined are developments in the miniaturized optical detection of ultrasound, which can transform any optical microscope into a hybrid optical-optoacoustic system. In addition, recent progress with label-free molecular sensing and with new classes of novel reporters that expand the visualization capacity of the optoacoustic method are presented. Finally, how hybrid optical-optoacoustic microscopy offers a next step in multimodal interrogations, thereby impacting biological and clinical readings, is discussed.