Preface

More than 40 years after its inception, DNA nanotechnology continues to evolve and advance at a rapid pace. In recent years, the world has experienced significant changes and faced numerous challenges, all of which have impacted or will impact the field of DNA nanotechnology. It is impossible not to mention that Ned Seeman, the father of DNA nanotechnology, passed away on November 16, 2021. His legacy is everlasting, and his absence is deeply felt. Ned contributed a fun and interesting historical opening chapter to the second edition of this book, a true gift to me and the readers. Between the publication of the second and this third edition, the world was shaken by the COVID-19 pandemic, causing incalculable damage to society and resulting in over 7 million deaths to date. One significant action that helped the world regain its footing was the development of new vaccines against SARS-CoV-2. These vaccines not only addressed the disease but also marked a significant push toward the mainstreaming of nanomedicine and RNA therapy. Although nanosized drug delivery systems were already in use, for example for anticancer drugs, the nanoformulation of the COVID vaccine represented a large-scale deployment and the first massive administration of nanodrugs to healthy indivi- duals. The RNA-based COVID vaccine also sparked renewed interest in RNA therapy and nucleic acid-based drugs. The near future will undoubtedly see more RNA vaccines and DNA drugs, with DNA nanotechnology potentially playing a role in making these drugs more effective, specific, personalized, and safe. RNA vaccines against cancer are already in development and will play a crucial role in this defining battle of our era. In this book, readers will find various methods to create and use nanostructures for characterizing, targeting, and controlling the behavior of cells. The current and future applications of DNA nanostructures in biotechnology and nanomedicine are experiencing significant development and success. Another recent watershed moment in our society has been the introduction of genera- tive AI tools to the public, such as the launch of ChatGPT in lateNovember 2022. Although deep learning and other AI tools have been used and developed in scientific research and customer interactions for decades, the recent acceleration in AI applications, including large language models and image generation and analysis, has been remarkable. Activities that once required highly skilled personnel can now be significantly facilitated by AI. Soon, molecular modeling will be performed using natural language interfaces, while publicly available large languagemodels already offer invaluable assistance in computer coding. Some molecular modeling software that already provides AI interfaces includes DNA nanotech- nology plug-ins. Further developments will make the design of DNA nanostructures significantly easier and more accessible to a larger community of researchers and technicians, potentially also interfacing with open data repositories of biological information. The near future promises to bring new and innovative ways to develop and utilize DNA nanotechnology. In this methods book, many authors share their procedures for designing, preparing, characterizing, and using DNA nanostructures, especially toward biological or materials science applications. Additionally, contributions to the study of fundamental aspects of nucleic acids, such as their pairing and stacking energy measured with optical tweezers, and the targeted delivery of lipid-encapsulated nucleic acid drugs aim to complete the landscape of nanoscale nucleic acids methods. DNA nanotechnology certainly has a bright future, and the sharing of experimental methods will contribute to making its progress more robust and its applications within reach of all interested researchers and technologists.