Using Paper-Based Diagnostics with High School Students To Model Forensic Investigation and Colorimetric Analysis

Emerging paper-based diagnostics is an inexpensive yet elegant approach to medical diagnostics and environmental testing in resource-poor regions of the world. Wicking by capillary action distributes a small drop of sample to reagent or assay zones without the need for pumps, refrigeration, or electricity. The advantages of using paper for medical diagnostics (low expense, availability, portability, easy disposal) also apply to the classroom. This article describes a two-session high school activity that employs a paper device to solve a crime scene mystery. On the first day, students role-play either suspects or a detective and make inferences to predict the guilty party. In the second session, students perform presumptive, paper-based forensic testing of "unknown" liquids retrieved from the suspects' homes and compare these findings with their predictions. The primary goals of this exercise are to demonstrate the similarities between forensic investigation and scientific inquiry and to introduce students to presumptive colorimetric analysis and to the promise of paper-based diagnostics and testing.