Nano-bio Interactions in the Lung

Understanding interactions between nanoparticles (NPs) and living organisms is of crucial importance for advancing biomedical applications such as NP-based drug delivery and for regulating the environmental, health, and safety (EHS) issues of nanotechnology. Among all potential portals of entering the human body, the respiratory system is the most susceptible to particle invasion due to its large surface area in direct contact with the environment. The large surface area and extremely thin diffusion barrier of the lung facilitate transportation and absorption of small molecules and macromolecular therapeutic agents, which makes the lung a promising portal for noninvasive drug delivery, not only topically to the lung but also systemic delivery to other targets. Hence, understanding nano-bio interactions in the lung plays an utmost important role in designing novel safe pulmonary drug delivery platforms and in mitigating the EHS impacts of particulate air pollutants or other pathogens. This chapter introduces fundamental physiology of the respiratory system, biophysical mechanisms for bio-nano interactions in the lung, and their impacts on pulmonary drug delivery and EHS issues related to nanotechnology. Focus is given to biomedical applications of nanomedicines to treat various respiratory and systemic complications, such as lung cancer, pneumonia, cystic fibrosis, tuberculosis, acute lung injury, and diabetes. The potential toxicity of NPs to the pulmonary surfactant, alveolar epithelium, and immune system is also discussed.