Modular bone implants, means of assembly, and their method of use are presented. The instrument is particularly adapted for dispensing multicellular test organisms like nematodes or large microspheres for use in screening large libraries of potential pharmaceutical agents. The polar group-containing olefin copolymer can be prepared by polymerizing the -olefin with the polar group-containing monomer andor the macromonomer in the presence of a metallocene catalyst.