BIOPRINTING OF MICRODISSECTED TUMOR "CUBOIDS" IN HYDROGELS.

Microscale tumor models made from microdissected tumors that retain much of the original human tumor microenvironment (TME) are emerging as an alternative to preclinical animal models. We have introduced a drug testing approach that utilizes regularly-cut, cuboidal-shaped microdissected tissues, or "cuboids," as a way to maximize creation of microtissues from scarce biopsy materials. However, microtissues (e.g., cuboids, organoids, spheroids, etc.) can be difficult to place in precise locations, especially in applications that require their culture in hydrogels. Here, using cuboids from mouse tumor models, we demonstrate a simple bioprinting strategy for precise placement and immobilization of cuboids in hydrogel. We use a commercial bioprinter to bioprint -containing hydrogel into arrays of small hydrogel dots containing cuboids, or "cuboid dots," either onto a Transwell insert or into traps on a microplate. The hydrogel serves to immobilize the cuboids in place and provides a matrix to support cuboid viability. We demonstrate proof-of-concept applications for cancer drug testing and for protein profiling analysis. This approach will enable interface of cuboids with other devices, such as on top of a sensor or in a microfluidic platform. Furthermore, this automated process of dispensing and localizing cuboids (or other microtissue formats such as spheroids or organoids) could further their application to drug discovery and personalized medicine.