Engineering strategies for drug delivery [Introduction to the special issue]

A drug is a molecule that changes physiological functions when absorbed into the cells or tissues of a living organism. It can be used to treat, cure, prevent, or diagnose diseases or to enhance physical or mental health. However, the discovery of a drug is an expensive, long, and challenging process. It can take 15 years for a big pharmaceutical company to spend more than US$500 million for developing a new drug. Despite the high cost, many drugs themselves can only provide the human being with modest desired effects. Moreover, almost all drugs can cause side effects when they act in the body. Therefore, there is a clear need to maximize the efficacy of a drug and simultaneously reduce its side effects. To achieve this goal, it is necessary to find a way to help drugs to primarily reach the target area of the body (e.g., solid tumors). Drug delivery is the right discipline for studying methods for administering drugs in a safe and efficient manner. The success of this discipline relies on different expertises from chemists, biologists, and engineers. In this special issue of IEEE Engineering in Medicine and Biology Magazine, we will particularly illustrate the significance of engineering knowledge in drug delivery through a collection of six articles from experts in the field.