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ABSTRACT Combinatorial phage display with a pVIII library of M13 bacteriophage was used to identify a peptide sequence capable of recognition and mineralization of copper sulfide. The six sequences isolated from the final biopanning round were rich in basic, hydrophobic, and polar amino acids compared to the phage display library. The peptide sequence, DTRAPEIV, was used to biomineralize copper sulfide on the pVIII major coat protein thus producing linear chains of nanoparticles. Electron microscopy revealed that the phage was capable of controlling the size of the nucleated nanoparticles in an aqueous solution at room temperature and that the mineralized material was copper sulfide. Phage-templated biomineralization is a low temperature, aqueous-based approach to synthesis of copper sulfide nanoparticles with hierarchical order. 

Copper sulfide-based ammonia (NH3) gas sensors were assembled using a genetically modified viral template. Glutamic acid residues on the filament-shaped bioscaffold surface facilitated the synthesis of nanocrystalline Cu1.8S. Each device comprised a network of biological materials decorated with a nonstoichiometric semiconductor. These chemiresistive devices had high sensitivity to NH3 concentrations from 10 to 80 ppm under room-temperature operation. Response times greater than 15 min were observed. These results demonstrate the potential of biotemplated materials for sensitive gas detection at room temperature. 

Organized chains of copper oxide nanoparticles were synthesized, without palladium (Pd) activation, using the M13 filamentous virus as a biological template. The interaction of Cu precursor ions with the negatively charged viral coat proteins were studied with Fourier transform infrared spectroscopy, transmission electron microscopy, and energy dispersive x-ray spectroscopy. Discrete nanoparticles with an average diameter of 4.5 nm and narrow size distribution were closely spaced along the length of the high aspect ratio templates. The synthesized material was identified as a mixture of cubic Cu2O and monoclinic CuO. UV/Vis absorption measurements were completed and a direct optical band gap of 2.87 eV was determined using Tauc's method. This value was slightly larger than bulk, signaling quantum confinement effects within the templated materials. 

The optical and electrical stabilities of viral-templated non-stoichiometric copper sulfide, digenite (Cu1.8S) films were investigated. The films were composed of large agglomerates of randomly aligned Cu1.8S-coated M13 filamentous phage. Free carrier optical absorption associated with localized surface plasmon resonance (LSPR) was observed in the near infrared spectral region, and the films were electrically active, displaying a linear current-voltage relationship. Under ambient conditions, the magnitude of the LSPR absorption increased, following a power law relationship with time, and the electrical resistance of viral-templated films decreased significantly. In contrast, the resistance of films stored under low oxygen, low humidity conditions experienced a smaller reduction in electrical resistance. Changes in optical and electrical film properties under ambient conditions were associated with an increase in free carrier concentration within the copper chalcogenide material due to oxygen exposure. X-ray photoelectron spectroscopy was used to relate this increase in free carrier concentration to compositional changes on the viral-templated material surface. 

The growth of crystalline copper sulfide using a viral template was investigated using sequential incubation in CuCl2 and Na2S precursors. Non-specific electrostatic attraction between a genetically-modified M13 bacteriophage and copper cations in the CuCl2 precursor caused phage agglomeration and bundle formation. Following the addition of Na2S, polydisperse nanocrystals 2–7 nm in size were found along the length of the viral scaffold. The structure of the copper sulfide material was identified as cubic anti-fluorite type Cu1.8S, space group, Fm3m. Strong interband absorption was observed within the ultraviolet to visible range with an onset near 800 nm. Furthermore, free carrier absorption, associated with the localized surface plasmon resonance of the copper sulfide nanocrystals, was seen in the near infrared with absorbance maxima at 1060 nm and 3000 nm, respectively. 

As science teachers, you observe excitement among your middle school students when they build things, tinker with materials, and work together. The engineering design practices included in the K–12 Framework for Science Education (NRC 2012) are an attempt to harness this excitement and enthusiasm for science and engineering. Integrating engineering design into your laboratory science teaching is an engaging way to support students in learning mathematics and science concepts (Katehi, Pearson, and Feder 2009). This article describes how the three of us (an education professor, a middle school teacher who implements engineering design activities as part of a green STEM curriculum, and an engineering professor) built on student thinking to design a weeklong unit on solar energy that supported mathematics and science learning. The lesson included students designing and redesigning a model solar car and culminated in a model-solar-car race. 

The purpose of this study is to describe how analyzing student work can be used to help undergraduates reflect on the effectiveness of their service-learning experiences. The service-learning collaboration between a university and middle school was designed to increase undergraduates’ and middle school students’ knowledge of solar energy. Three undergraduates enrolled in a service-learning course that covered basic solar energy concepts and formative assessment instructional strategies. The focal point of the course was the implementation of several activities in a middle school classroom that addressed middle school students’ misconceptions about solar energy, such as the amount of solar energy production at low temperatures or on a cloudy day. Data from this study includes student work during a small-group activity on solar cells. Findings suggest that undergraduates can analyze student work and use this information to better understand how their efforts can influence middle school student learning of solar energy. 

The purpose of this study is to describe the effects of collaboration between a university and middle school that was designed to increase middle school students’ knowledge of solar energy. Three undergraduates enrolled in a service-learning course that covered basic solar energy concepts and formative assessment instructional strategies. The focal point of the course was the implementation of several activities in a middle school classroom that addressed middle school students’ misconceptions about solar energy, such as the amount of solar energy production at low temperatures or on a cloudy day. Data from this study include student performance on a written assessment, individual interviews, and student work. Findings suggest that although middle school students who participated in the activities increased their general knowledge of solar cells, many of the students’ conceptions about how exactly solar cells work were fairly persistent. This paper provides useful information on K-12 outreach efforts that can help students acquire the dispositions and knowledge they need in order to participate in STEM fields.