This thesis focuses on two studies conducted through the professional development program of the National Center for Learning and Teaching in Nanoscale Science and Engineering (NCLT). The first project described is a study of our own lesson planning process using a design-based research framework. Major findings from this study relate to teachers’ development of concept knowledge, teacher attitudes towards a particular lesson on nanoscale phenomena, and recommendations for future iterations of this lesson. The second is an analysis of teacher lesson plans relating to nanoscale science, engineering, and technology. This study presents findings related to lesson design, what types of content teachers see as relevant to their classrooms, and how teachers fit this content into their existing curricula. These studies have implications for design of nanoscience professional development programs, as well as for the design of other innovative professional development programs and for inquiry-based curriculum development in general.