Micro- and nanostructures are found widely in nature and are important for the development and maintenance of organisms. Fabricated structures of dimensions corresponding to native biological structures may be obtained by methods such as laser-based fabrication and are of special relevance to applications in biology and medicine, as they impact cellular behavior. In this review, we will examine how fabricated structures of a particular length scale interact with natural structures of corresponding dimensions to produce the designed response, thus giving readers a primer on how laser-based fabrication may be fruitfully applied to biomedicine. Lasers have been used to fabricate nanopores for a variety of applications at the molecular level, such as the analysis of DNA. At the subcellular level, microstructures such as elastic beams fabricated by laser direct writing have been used to adhere and interact with cells. In the area of tissue engineering, an important application of micro- and nanostructures is related to their ability to control intercellular interactions. The fabricated structures facilitate the positioning of cells with respect to each other, so as to simulate the complexity of native tissues. Focused laser sources have also been used to create channels modified with functionalities to help guide cell migration.