Autonomous Soft Nanorobots for Active Targeting and Therapy of Triple-Negative Breast Cancer

The extensive connective tissue proliferation and dense extracellular matrix (ECM) in triple-negative breast cancer (TNBC) form abnormal physical barriers that impede the penetration of nanomedicines and hinder therapeutic efficacy. Herein, autonomous soft nanorobots with TNBC-targeted ability are reported for enhanced photodynamic therapy. The nanorobots (denoted as CAT-P@Ce6) are composed of catalase (CAT), targeting peptide P25343, and photosensitizer Ce6. The CAT-P@Ce6 nanorobots possess an inwardly concave and wrinkled structure with a uniform diameter of 256 nm. Representative motion trajectories and transwell migration assay of the CAT-P@Ce6 nanorobots demonstrate their excellent propulsion performance. Co-incubation experiments with MDA/MB-231 cells and 3D multicellular tumor spheroids show enhanced cellular internalization efficiency of the CAT-P@Ce6 nanorobots, attributed to their targeting, migration, and soft properties. Furthermore, flow cytometry shows that the soft nanorobots functionalized with the targeting peptide P25343 exhibited a 1.82-fold increase in fluorescence intensity compared to rigid and non-targeted nanoparticles. Cellular and colony formation experiments reveal an efficient anti-tumor cell proliferation effect of the CAT-P@Ce6 nanorobots. In vivo experiments further demonstrate that the TNBC-targeted nanorobots significantly inhibit tumor growth. The design of soft nanorobots with active targeting ability offers a promising strategy for overcoming dense tumor physical barriers and enhancing intratumoral penetration.