Controlled Drug Delivery from Alginate Spheres in Design-based Learning Course

Engineering design is a central concept driving our engineering curriculum and an integral component of the practice of engineering. Frequently, design concepts are not introduced in Biomedical Engineering at the university level until the last year of the undergraduate curriculum, generally in the form of a Senior Design course. Though students have been widely exposed to the scientific method, many reach their senior year in college surprised to find out that a design method also exists. Design is characterized by an iterative sequence of steps that involve identifying a need, defining the problem, developing solutions, evaluating solutions, and communicating results and recommendations. Seniors consistently requested, through exit surveys, introduction to design earlier in their academic experience. Furthermore, earlier introduction to design has also recently been recognized as a retention tool of engineering students because they are able to understand the dynamic and creative nature of engineering, a topic often lost in the first two years of engineering. In order to provide early and consistent exposure to the engineering design process, we have implemented a design-based laboratory course featuring experiments in biomaterials design and drug delivery. Controlled drug delivery is an important application of biomedical engineering incorporating key aspects of mass transport, physiology, and biomaterials. This lab segment, which spanned five laboratory sections and four 1 hour lectures, led the students through the design, synthesis, and characterization of a particle-based matrix drug delivery device using ionically-crosslinked alginate spheres and several model drugs, fluorescein, tartrazine, erythrosin B, and bovine serum albumin. The experimental portion of the module included the synthesis of crosslinked alginate spheres of differing sizes, automated sizing of the spheres using microscopy and ImageJ, loading of a model drug into the spheres using equilibrium sorption or dispersed encapsulation, and the quantification of the dye release using absorbance on a UV/Vis plate reader. Students were evaluated by review of their laboratory notebooks, including methods, observations, calculations, and relevant plots. Additionally, assigned background research, which consisted of sourcing information from scientific literature and online resources, was recorded in the notebook. Ultimately, this course is an interesting approach to provide the first-year students an overview of what the biomedical engineering field encompasses by providing hands-on experience in several different areas of research and getting the students excited about their field of study. Analysis of course surveys revealed a significantly greater perceived course value relative to the previous seminar-based course.