Confocal imaging of the embryonic heart: how deep?

Confocal microscopy allows for optical sectioning of tissues, thus obviating the need for physical sectioning and subsequent registration to obtain a three-dimensional representation of tissue architecture. However, practicalities such as tissue opacity, light penetration, and detector sensitivity have usually limited the available depth of imaging to 200 microm. With the emergence of newer, more powerful systems, we attempted to push these limits to those dictated by the working distance of the objective.