Detachable head-mounted photoacoustic microscope in freely moving mice

• Published in: Optics letters 2021-12, Vol.46 (24), p.6055-6058
• Main Authors: Guo, Heng, Chen, Qian, Qin, Wei, Qi, Weizhi, Xi, Lei
• Format: Article
• Language: English
• Subjects: Animals; Cerebral cortex; Field of view; Image quality; Laser beams; Mice; Microscopy; Mouse devices; Photoacoustic microscopy; Piezoelectricity; Ultrasonic testing; Ultrasonics
• ISSN: 0146-9592; 1539-4794
• DOI: 10.1364/OL.444226

Optical resolution photoacoustic microscopy (ORPAM) is a promising tool for investigating anatomical and functional dynamics in the cerebral cortex. However, observation in freely moving mice has been a longstanding challenge for ORPAM. In this Letter, we extended ORPAM from anesthetized, head-restrained to awake, freely moving mice by using a detachable head-mounted ORPAM probe. We used a micro-electro-mechanical-system scanner and a miniaturized piezoelectric ultrasonic detector to scan the excitation laser beam and detect generated photoacoustic signals, respectively. The probe weighs 1.8 g and has a large field of view of ∼3 ×3 . We evaluated the performance of the probe by carrying out phantom experiments and the imaging of vascular networks in a mouse cerebral cortex. The results suggest that the ORPAM probe is capable of providing stable and high-quality ORPAM images in freely moving mice.