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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. [ABSTRACT FROM AUTHOR]

Interactions of a peptide with polyproline II helical secondary structure with maghemite (iron(III) oxide, Fe2O3) surfaces were characterized using a variety of surface techniques. A quartz crystal microbalance with dissipation was used to measure the hydrated mass and thickness (92 ± 29 ng/cm2 and 0.89 ± 0.27 nm, respectively) of a layer which formed after a sensor coated with Fe2O3 was exposed to the peptide in aqueous solution. The analysis revealed that the peptide formed a stable thin layer on the sensor. X‐ray photoelectron spectroscopy and Fourier‐transform infrared spectroscopy of the monolayer were employed to study the relationship between the metal and the peptide. Finally, Fe2O3 nanoparticles were incubated with the peptide, and analysis of the settling and particle size revealed that the presence of the peptide reduced the occurrence of large aggregates in solution. [ABSTRACT FROM AUTHOR]

Human mesenchymal stem cells (MSCs) are attractive for use in cartilage tissue engineering. Cells are often seeded in a structural scaffold containing growth factors. Peptide mimics of full-length growth factors are a promising alternative because they are less expensive and easier to manufacture. We investigated four short peptides for their effect on the chondrogenesis of human MSCs. The peptides were originally designed to mimic bone morphogenetic protein-2 (BMP-2), transforming growth factor-beta 1 (TGF-β1), and insulin, all of which have been shown to affect MSC chondrogenesis. Previous studies demonstrated that the peptides elicited bioactivity in other cell types, but the peptides have not been investigated for their effect on chondrogenesis in human MSCs. In a preliminary investigation, peptides were added to a pellet culture of human MSCs and assayed for their effect on glycosaminoglycan (GAG) production. These experiments determined peptide concentrations used in a full-factorial experiment to investigate any interactions. The experiment revealed the BMP peptide as a robust stimulant for GAG production. © 2013 American Institute of Chemical Engineers Biotechnol. Prog., 29:1550-1557, 2013 [ABSTRACT FROM AUTHOR]

The article discusses the program for female high school students to increase their knowledge about the engineering profession through the enhancement of awareness of both chemical and tissue engineering to help them form stronger opinions about future careers. The activity, part of the Exciting Discoveries for Girls in Engineering (EDGE) Summer Camp sponsored by the Women in Engineering Program at Purdue University, included interactive discussions, and a hands-on laboratory component.

Cerium has a wide range of current and emerging applications, and the binding of cerium ions to solid substrates is important for cerium recovery, or in advanced material synthesis. In this study, we investigate the affinity of a surface‐bound peptide derived from the EF‐hand loop I of calmodulin for cerium (III) ions and compare the results to a scrambled control. Results obtained via quartz crystal microbalance with dissipation are used to estimate the dissociation constant between the bound EF‐hand loop I peptide and cerium (III) ions (1.3 ± 0.1 μM), which is comparable with other dissociation constants measured for EF‐hand peptides and cerium ions in solution reported this work and in literature (0.95‐5.8 μM). Circular dichroism also suggests that the peptide binds to cerium (III) ions in solution, and undergoes a secondary structural change upon binding. Overall, this study shows that EF‐hand loop peptides are capable of binding cerium (III) ions in solution and when attached to a solid substrate. [ABSTRACT FROM AUTHOR]