Nanorobotics at a crossroads: an overview of design, propulsion, and applications.

Nanobots are small nanoscale devices designed to perform highly specific tasks in precisely targeted areas, representing a promising approach in the diagnosis and treatment of various diseases. This review describes the ideal characteristics and attributes of these systems, including their dimensions and the most commonly used materials. It also analyses the main propulsion mechanisms that enable their locomotion in biological environments, comparing them in terms of efficiency, biocompatibility, and therapeutic potential. Although these devices may have several therapeutic applications, the primary focus is on oncology, given their ability to deliver drugs directly to the tumor site, thereby minimizing chemotherapy-related side effects. Furthermore, the main challenges to their clinical application are discussed, particularly those related to propulsion systems, physiological barriers, and regulatory issues. In this context, relevant patents are presented to highlight the growing interest and technological advancements in clinical nanorobotics.