With new K−12 national science standards emerging, there is an increased need for experiments that integrate engineering into the context of society. Here we describe a chemistry experiment that combines science and engineering principles while introducing basic polymer and green chemistry concepts. Using medical sutures as a platform for investigating polymers, students explore the physical and mechanical properties of threads drawn from poly(ε-caprolactone) samples of different molecular masses and actual purchased absorbable and nonabsorbable medical sutures. An inquiry-based part of the experiment tasks students with designing their own experiment to probe the potential of melt blending poly(ε-caprolactone) with commercially available polylactide products in order to modify the properties of the "sutures" drawn. Through these lessons students gain an appreciation for the importance of plastics in our society and how scientists are working to develop more sustainable alternatives. Overall, this laboratory experiment provides a feasible, versatile, sophisticated laboratory experience that engages students in a relatable topic and meets many of the Next Generation Science Standards.

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The goal of this study was to create an accessible, inexpensive, and engaging experiment to teach high school and undergraduate chemistry or biology students about intermolecular forces and how they contribute to the behavior of biomolecules. We developed an enzyme-linked immunosorbent assay (ELISA) to probe specific structure–function relationships in the context of a protein–protein interaction that can be completed within a week of 45 min daily classes or a single 3–4 h lab using accessible reagents and materials (e.g., micropipettes and camera phones). The assay detected the high-affinity interaction between immunoglobulin G (IgG) and an engineered fibronectin domain protein. To demonstrate the impact of small chemical changes on intermolecular interactions, four mutant fibronectin domains were engineered, each with a single amino acid change, to provide a variety of chemical groups in the hypothesized binding site that resulted in a range of affinities for IgG (equilibrium dissociation constants from 1.5–696 nM). The experiment was implemented with two classes of high school chemistry students. Students effectively differentiated between strong and weak protein–protein interactions (median correlation coefficient between observed and expected results = 0.88) and demonstrated keen interest in the assay and concepts. Students were asked to then design and conduct a variation of the ELISA to test their own hypotheses regarding various experiment parameters to great success. Image acquisition for assay colorimetry was identified as a potential area of improvement. We have shown that this experiment is accessible to high school students both fiscally and academically and can be a fun and effective tool to apply their knowledge of intermolecular forces within the context of proteins. We have shown that the experiment could also be implemented in an undergraduate laboratory setting to allow for advanced inquiry into protein–protein interaction quantification and data analysis. This experience helps students at a variety of academic levels make conceptual connections across the fields of chemistry, physics, and biology.

A passive visual end of service life indicator (ESLI) for certain organic vapors has been attached to the inside wall of an organic vapor respirator cartridge. The opposite side of the ESLI touches activated carbon inside the cartridge. During use, organic vapors moving through the cartridge adsorb into both the carbon and the ESLI. The cartridge body is clear so that when vapor concentrations meet a certain threshold, the user may observe the progressive development of an indicator bar down the side of the ESLI. The cartridge is deemed ready to change when any part of the indicator bar touches a marked end line. The performance of the ESLI was observed when the cartridge was tested against a variety of organic vapors, exposure concentrations above the minimum indication level, humidities, temperatures, flow rates, and mixtures. In all cases, the ESLI indicated end of service life with more than 10% cartridge service life remaining (which is a NIOSH test criteria). The results were also compared to mathematical predictions of cartridge service life.

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