Page 14 - C. Biotechnology and molecular imaging

[C. Biotechnology and molecular imaging-9]

[Part 2] A Novel Tool for Comparative Analyses of Clearing

Efficacies of Tissue Clearance Protocols

Jiwon Woo¹˙²˙, Jeong-Yoon Park¹˙², Yong-Eun Cho¹˙²˙*

¹Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul 03722, Republic of Korea, ²The Spine

and Spinal Cord Institute, Department of Neurosurgery, Gangnam Severance Hospital, Yonsei University College of
Medicine, Seoul 06273, Republic of Korea

The advent of tissue clearing methods, in conjunction with novel high-resolution imaging techniques, has enabled

the visualization of three-dimensional structures with unprecedented depth and detail. Although a variety of clearing

protocols have been developed, little has been done to quantify their efficacies in a systematic, reproducible fashion.
Here, we present two novel assays, PACA (Punching-Assisted Clarity Analysis)-Light and PACA-Glow, which use easily
accessible spectroscopy and gel documentation systems to quantify the transparency of multiple cleared tissues

simultaneously. We demonstrate the use of PACA-Light and PACA-Glow to compare twenty tissue clearing protocols
on rodent brains. We also show that there are regional differences in tissue transparency in the rodent brain, with

cerebellar tissue consistently achieving lower clearance levels compared to the prefrontal or cerebral cortex across
all protocols. This represents the largest comparative study of tissue clearing protocols to date, made possible by

the high-throughput nature of our PACA platforms.