Metastatic relapse,development of drug resistance in cancer cells and adverse side effects of chemotherapeutic agents are the major obstacles for effective chemotherapy against triple-negative breast cancer.To address these problems,nanocarriers have been largely developed to encapsulate and deliver therapeutic agents and attracted increasing attention in miRNA delivery.In addition to nanocarriers designed to deliver a single therapeutic agent,there are growing interests in developing multi-agent co-delivery nanocarriers that can simultaneously incorporate and deliver multiple types of therapeutic payloads to disease sites in a targeted and controlled manner for combined therapy.