In this research, Ag‐Al2O3 nanostructures have been prepared via combustion synthesis and ammonium acetate and urea have been applied as fuels. The prepared Ag‐Al2O3 nanostructures were characterized by DTA, XRD, SEM, TEM, and BET spectroscopy. The effect of different ratios of silver to alumina and fuel percentage on morphology and particle size of prepared products were investigated. The results showed that using ammonium acetate fuel led to the production of Ag‐γ‐Al2O3 nanocompounds, while using urea produced Ag‐α‐Al2O3. Also, the photocatalytic activity of Ag‐Al2O3 nanostructures for Congo red degradation was evaluated by UV‐Vis diffuse reflectance spectroscopy. The photocatalytic activity of Ag‐Al2O3 was examined under UV‐Vis irradiation and showed significant photocatalytic efficiency.

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Surface-grafted elastin has found a wide range of uses such as sensing, tissue engineering and capture/release applications because of its ability to undergo stimuli-responsive phase transition. While various methods exist to control surface grafting in general, it is still difficult to control orientation as attachment occurs. This study investigates using an electric field as a new approach to control the surface-grafting of short elastin-like polypeptide (ELP). Characterization of ELP grafting to gold via quartz crystal microbalance with dissipation, atomic force microscopy and temperature ramping experiments revealed that the charge/hydrophobicity of the peptides, rearrangement kinetics and an applied electric field impacted the grafted morphology of ELP. Specifically, an ELP with a negative charge on the opposite end of the surface-binding moiety assembled in a more upright orientation, and a sufficient electric field pushed the charge away from the surface compared to when the same peptide was assembled in no electric field. In addition, this study demonstrated that assembling charged ELP in an applied electric field impacts transition behavior. Overall, this study reveals new strategies for achieving desirable and predictable surface properties of surface-bound ELP.

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Active Janus colloids are functional particles that combine two distinct chemical or physical surface properties. The anisotropic nature of this class of patchy particles allows them to harvest and redirect energy to create a local force that leads to autonomous motion. Modulating the surface forces experienced by or the responsiveness of a Janus particle's surface offer an avenue of further control. There are broad efforts in the community to advance the fundamental understanding of and engineer such control into active systems. This article aims to summarize recent work in catalytic active Janus colloids, peptide and polypeptide engineering and design, and present work showing how engineered polypeptides can be used to control motion of catalytic active particles. Experiments probing nonspecific effects are reviewed that measured the active motion of 5 μm catalytic Janus spheres in the presence of low molecular weight polyethylene glycol (PEG). Previous work has found that at infinitely dilute concentrations of particles, the addition of PEG in solution reduced particle propulsion speed. Further increasing particle concentration led to increased clustering at low concentrations of PEG, but clustering was then reduced at high concentrations of PEG. These results inspired work presented herein with 3 μm particles that shows platinum binding peptides that specifically attach to the platinum cap reduced the propulsion speed. These data support a pathway for using engineered peptides as tools for controlling the activity of catalytic active Janus particles. Overall, this article highlights how nonspecific and specific molecular interactions can achieve control in active systems.