Background: Solid nanostructures are versatile platforms for constructing hybrid drug delivery systems that have tremendous potential for improving disease prevention and treatment. The rationale and application of solid nanostructures in the context of drug delivery are explored in this article. Objective: The purpose of this paper is to provide a concise review of the major attributes of solid nanostructures as they relate to drug delivery and to describe the outstanding issues that need to be addressed in order to develop these materials into clinically useful reagents. Methods: The scope of this opinion has been restricted to solid nanostructures, where solid nanostructures are defined as those that are not biodegradable. The opinion has been further limited to the three primary types of nanostructures: nanoparticles, nanowires and nanotubes. Results/conclusion: There is a need for cross-disciplinary training and standardized protocols for developing and evaluating the efficacy of solid nanomaterials.