PICS: a platform for planar imaging of curved surfaces of brain and other tissue
Optical imaging of wholemount tissue samples provides greater understanding of structure–function relationships as the architecture of these specimens is generally well preserved. However, difficulties arise when attempting to stitch together images of multiple regions of larger, oddly shaped specimens. These difficulties include (1) maintaining consistent signal-to-noise ratios when the overlying sample surface is uneven, (2) ensuring sample viability when live samples are required, and (3) stabilizing the specimen in a fixed position in a flowing medium without distorting the tissue sample. To address these problems, we designed a simple and cost-efficient device that can be 3D-printed and machined. The design for the device, named the Platform for Planar Imaging of Curved Surfaces (PICS), consists of a sample holder, or “cap” with gaps for fluid flow and a depression for securing the sample in a fixed position without glue or pins, a basket with two arms that move along an external radius to rotate the sample around a central axis, and a customizable platform designed to fit on a commercially available temperature control system for slice electrophysiology. We tested the system using wholemounts of the murine subventricular zone (SVZ), which has a high degree of curvature, to assess sample viability and image quality through cell movement for over an hour for each sample. Using the PICS system, tissues remained viable throughout the imaging sessions, there were no noticeable decreases in the image SNR across an imaging plane, and there was no noticeable displacement of the specimen due to fluid flow.
KeywordsWholemount imaging Multiphoton imaging 3D printing Open source design Subventricular zone Cytoarchitecture
We would like to thank Dr. Francis Szele, Oxford University, UK, for inspiring us to create this device and for the use of his Bioptechs TC3 warming system to test the device. Graduate support was provided by a National Institutes of Health grant R21NS090131 (BSK) and a Louisiana Board of Regents Graduate Fellowship (JLS). Funding was also provided by the Edmondson/Crump Endowed Professorship, Louisiana Tech University (TAM).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
Statement on the welfare of animals
All applicable international, national, and/or institutional guidelines for the care and use of animals were followed. All procedures performed in studies involving animals were in accordance with the ethical standards of the Louisiana Tech University Institution Care and Use Committee. This article does not contain any studies with human participants performed by any of the authors.
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