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With a growing number of global challenges related to the environment, water, public health, and energy, there is an imminent need to teach chemistry in the context of its interconnectedness with other systems. Project-and problem-based learning are student-centered learning approaches which offer educators the opportunity to engage learners in solving complex real-world problems. By choosing a globally relevant project/problem and requiring students to utilize scientific methods to solve the problem, both problem-based learning and project-based learning are excellent strategies for educators to teach chemistry using a systems approach. This review summarizes key research studies which utilize project-and problem-based learning in the context of enabling learners to confront global problems and the wide applicability of these approaches to systems thinking.

Over the past decade, poly(3,4-ethylenedioxythiophene) (PEDOT) has been one of the widely investigated conjugated polymers due to its excellent electro-optical properties. The conventional synthesis of PEDOT/PSS involves oxidation of EDOT using strong oxidants in aqueous polystyrenesulfonate (SPS) solution. The low pH conditions and strong oxidants render this synthetic protocol unsuitable for use of PEDOT in applications such as biosensing. For the purpose of expanding the utility of PEDOT in these applications, it is important to develop a route that can provide the possibility of synthesizing PEDOT in the presence of the appropriate biological entities. Here we report the use of terthiophene as a radical mediator to synthesize PEDOT/PSS under milder pH conditions using soybean peroxidase (SBP). The oxidation potential of terthiophene is sufficiently low for initiation of the polymerization reaction catalyzed by SBP. The oxidized terthiophene helps the subsequent oxidation of EDOT, thus mediating the polymerization reaction. This novel approach involving the use of conjugated oligomers as redox mediators is generic and vastly expands the types of substrates (thiophenes, pyrroles) that can be polymerized using enzymatic methods and benign conditions.

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A novel biomimetic route for the synthesis of electrically conducting homopolymers/copolymers of pyrrole and 3,4-ethylenedioxythiophene (EDOT) in the presence of a polyelectrolyte, such as polystyrene sulfonate (SPS), is presented. A poly(ethylene glycol)-modified hematin (PEG-hematin) was used to catalyze the homopolymerization of pyrrole and EDOT as well as copolymerization of EDOT and pyrrole in the presence of SPS to yield homopolymers of polypyrrole/SPS and PEDOT/SPS as well as a polypyrrole-co-poly(3,4-ethylenedioxythiophene)/SPS complex. Spectroscopic characterization [UV−visible, Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS)], thermal analysis, (TGA), and electrical conductivity studies for these complexes indicated the presence of a stable and electrically conductive form of these polymers. Furthermore, the presence of SPS that serves as a charge-compensating dopant in this complex provides a unique combination of properties such as processability and water solubility.

In recent years, developing potent antioxidants has been a very active area of research. In this context, phenolic compounds have been evaluated for their antioxidant activity. However, the use of phenolic compounds has also been limited by poor antioxidant activity in several in vivo studies. Polymeric phenols have received much attention owing to their potent antioxidant properties and increased stability in aqueous systems. To be truly effective in biological applications, it is important that these polymers be synthesized using benign methods. In this context, enzyme catalyzed synthesis of polymeric phenols has been explored as an environmentally friendly and safer approach. This review summarizes work in enzymatic syntheses of polymers of phenols. Several assays have been developed to determine the antioxidant potency of these polymeric phenols. These assays are discussed in detail along with structure-property relationships. A deeper understanding of factors affecting antioxidant activity would provide an opportunity for the design of versatile, high performing polymers with enhanced antioxidant activity.

Enzymatic synthesis of doped polypyrrole (PPy) complexes using oxidoreductases (specifically peroxidases) is very well established "green" methods for producing conducting polypyrrole. The importance of this approach is realized by the numerous potential opportunities of using PPy in biological applications. However, due to very high costs and low acid stability of these enzymes, there is need for more robust alternate biomimetic catalysts. Hematin, a hydroxyferriprotoporphyrin, has a similar iron catalytic active center like the peroxidases and has previously shown to catalyze polymerization of phenol monomers at pH 12. The insolubility of hematin due to extensive self-aggregation at low pH conditions has prevented its use in the synthesis of conjugated polymers. In this study, we have demonstrated the use of a micellar environment with sodium dodecylbenzenesulfonate (DBSA) for biomimetic synthesis of PPy. The micellar environment helps solubilize hematin, generating nanometer size reactors for the polymerization of pyrrole. The resulting PPy is characterized using UV-visible, Fourier transform infrared, and X-ray photoelectron spectroscopy and reveals the formation of an ordered PPy/DBSA complex with conductivities approaching 0.1 S/cm.