Adapting his bottlebrush polymer drug delivery platform, Jeremiah Johnson has engineered new antibody-targeted particles that outperform existing antibody drug conjugates to deliver concentrated chemotherapy directly to cancer cells. The study, which appears in Nature Biotechnology, shows that each antibody-guided particle can carry dozens or hundreds of drug molecules tethered to polymer chains, eradicating most tumors in mouse models. This work was supported in part by the Koch Institute Frontier Research Program.