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Posted: June 1, 2010
LVEM5 used by US Air Force Research Laboratory to Create Novel Bioassembled Materials
(Nanowerk News) There is growing interest to create new materials with never-before-seen synergistic properties or additional functionality. One way to do this is to combine different materials, with different properties, together in order to create a new hybrid material. Often, it is a challenge to get these different materials together, especially at the nano-scale.
A recently published study in ACS Applied Materials & Interfaces, with authors from The Materials and Manufacturing Directorate at the US Air Force Research Laboratory, shows an interesting new way to do just that. The study, titled "Bioassembled Layered Silicate-Metal Nanoparticle Hybrids" uses a “biological blueprint” as a method to functionalize the surface of “layered aluminosilicate nanoparticles” with metal nanoparticles.
(A) Schematic illustration of the M13 bacteriophage showing the displayed peptides on the pIII coat protein. (B) Low-voltage transmission electron microscope (LVEM5) micrograph of MMT sheets incubated with phage displaying a non-specific peptide. (C) Low-voltage transmission electron microscope (LVEM5) micrograph of MMT sheets incubated with phage displaying the specific M1 peptide.
The usefulness of using molecular building blocks (amino acids, proteins, and enzymes) for designed organization of hybrid nanostructures has been shown many times in the past. For example, certain proteins have been shown to strongly bind to specific nanomaterials. In this way they can be used as biolinkers or “biological blueprint” to direct the assembly of materials into predefined structures. This study is one of the first times that the interactions between layered silicates and biological materials has been examined.
Layered aluminosilicate (LA) materials have been investigated for applications as diverse as polymer nanocomposites, drug delivery, sensing, and hemostatic agents among others. Many of these application areas would benefit from an increase the functionality of the LA. This is the goal of using the biological material to help guide the modification of the LA into more useful varieties.
This research shows that hybrid structures derived from a “biological blueprint” have been shown to have interesting new properties. For example some of these new hybrid nanoparticles are responsive to a weak external magnetic field that enables novel magneto-optical fluids. These fluids can be optically translucent or opaque, depending on the presence or absence of a magnetic field. Others display heating during exposure to RF radio waves. These functional properties have much value in applications ranging from sensors to cancer treatments.
The LVEM5 played an important role in this research. Due to the scale of the materials being studied, electron microscopy was needed to be able to evaluate the binding of the nanomaterials to the biological template, as well as understand if the materials were being assembled together as predicted. Conventional Transmission Electron Microscopy (TEM) requires that biological materials, such as phages, be stained with heavy metals in order to be resolved. In this study, the addition of heavy metal stains would make it difficult to understand if the phages are bound to the nano-materials. Low-Voltage Electron Microscopy (LVTEM) allows the operator to visualize biological materials at the nanoscale without the use of these destructive heavy metal stains.