Two-photon excited fluorescence microendoscopic imaging using a GRIN lens

Abstract

With the rapid development of life sciences, there is an increasing demand for intravital fluorescence imaging of small animals. However, large dimensions and limited working distances of objective lenses in traditional fluorescence microscopes have limited the imaging applications mostly to superficial tissues. To overcome this disadvantage, researchers have developed the graded-index (GRIN) probes with small diameters for imaging internal organs of small animals in a minimally invasive fashion. Here, we present the development of a fluorescence endoscopic imaging system based on a GRIN lens using two-photon excitation. Experimental results showed that this system could perform dynamic fluorescence microendoscopic imaging and monitor the blood flow in anesthetized living mice using two-photon excitation.

Imaging and analysis of genetically encoded calcium indicators linking neural circuits and behaviors

“…Conventional two-photon imaging necessitates undergoing cranial window surgery, which limits the possible imaging region of the cortex [20]. However, there is a new imaging technic combining two-photon microscopy and gradient index (GRIN) lens that enabled two-photon microscopy to overcome the limitation of imaging depth [9899100].…”