Electrochemical printing (EcP) is a software reconfigurable tool and process for electrodeposition of multi-scale, multi-material objects from input drawings. The EcP system—comprising custom LabVIEW print driver software, hardware, electrolyte and a microjet print nozzle—creates complex patterns by locally electroplating individual metal and alloy dots as the microjet rasters over a substrate. The rastering of a microjet just a few microns above the substrate provides extraordinary convective mass transfer rates, allowing material growth rates that are routinely two orders of magnitude greater than in conventional plating. EcP has the flexibility to vary the print resolution and material composition during the patterning process via real time control of the microjet fly height, electrolyte flow rate and applied current. Microjet fly-height is used to vary the print resolution from 50 to 1000 dots per inch during the printing of a copper pattern. Simultaneous control of electrolyte flow rate and applied current through the microjet nozzle is used to achieve high plating efficiencies, well-formed dots and alloys of specific compositions for the copper and nickel–copper systems. It is also shown that commercially available noble metal plating baths can be used in the EcP tool, despite the unusually large current densities achievable and the complexity of commercial bath additives. Issues associated with making EcP a robust tool for 2D and 3D microfabrication are discussed.

Peptides with inorganic materials recognition already started to impact a wide range of surface-related technologies ranging from biomonitoring to biomedical areas. Combinatorial biology-based libraries are the initial step in tempting the directed evolution of peptides with specific interactions towards technologically relevant materials. Here, a case study is provided to demonstrate the specific peptide binding and the amino acids residues that play an important role for platinum surface affinity by combining computational as well as genetic engineering tools. Using a phage display technique, septapeptides were identified exhibiting affinity to noble metal platinum, and the amino acid distributions in the identified peptides were analyzed. The analysis of the peptide sequences showed that strong Pt-binding peptides contain positively charged, hydrophilic, and polar residues, and especially enriched in threonine, serine, and glutamine. Under competitive surface-binding conditions, strong Pt-binding peptide motif displayed on phage resulted in high specificity to Pt regions on a Pt-macropatterned glass. Conformational analysis of the strong binder indicates that threonine and serine as well as glutamine are in close contact with the surfaces forming a tripod molecular architecture. The alanine substitution mutagenesis applied at the genomic level to the peptide displayed on the phage revealed threonine and serine substitutions as the critical ones. Understanding the residue-based interactions of the peptide sequences can be utilized to tune the affinity and the specificity of the peptides with the inorganic surfaces, toward making them indispensable molecular tools to control the molecular interactions of biological macromolecules with the material surfaces.

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After the events of 11 September 2001, the possibility of a dirty bomb being detonated within the United States seems more realistic. Development of tools for use in response to a dirty bomb detonation has become a topic of both discussion and research. While it has been reported that the health risk to the public from such an event would likely be small, it is thought that the psychological impact could be considerable. One response option that has been considered is adapting sprayable solutions for the purpose of fixing contamination in place, thereby limiting the spread of contamination by wind and rain and facilitating subsequent cleanup. This work evaluated two commercially available particle fixatives (IsoFIX-HT and IsoFIX-RC) for their effectiveness in preventing dispersal of simulated contamination. Nonradioactive cesium chloride and cobalt oxide particles were selected as the simulated contamination and applied to the surface of three outdoor test plots. Two test plots were treated with fixatives; the third plot provided a control. Samples were collected over 95 days to observe changes in tracer concentration on the surface of the test plots. One fixative (IsoFIX-RC) effectively held the tracer in place with no net loss of tracer, while the other fixative (IsoFIX-HT) had no impact on the loss of tracer relative to the control. Under the conditions tested, IsoFIX-RC appears capable of fixing surface contamination in place for at least several months.