A method for making a microarray block with a recipient block having at least one bore therein. A mold having a cylindrical bore with a cross-sectional shape approximating the cross-sectional shape of the at least one bore of the recipient block can be provided. The first end of the mold can have an opening that communicates with a cylindrical bore of the mold. A biological sample and a liquid carrier medium can be introduced through the opening and solidified in the mold to form a core. The core can be removed from the mold and at least a portion of the core can be inserted into the at least one bore of the recipient block. Related methods and assemblies are provided.