Book excerpt: The book focuses on the application of nanotechnologies in scaffold-guided tissue regeneration and in drug delivery systems for use in immunotherapy and overcoming drug resistance in cancer treatment. It covers a variety of topics, including nanomaterials for immunomodulation and immnunotherapy; molecular studies on self-assembly for peptides and DNA and related applications in tumor diagnosis and therapeutics and against human pathogenic bacteria; magnetic and conductive scaffolds for guiding tissue regeneration; multiple functions of magnetic nanoparticles in drug delivery and regenerative medicine; and re-purposing of traditional medicine in nano-formulations. In addition, it discusses common effects of nanomaterials, including reactive oxygen species and protein corona. Providing valuable insights and the presenting the latest research advances, the book allows readers to gain a systematic understanding of the topic.