A LVEM5 electron microscope will soon be installed at Yonsei University, Korea, in the Department of Materials Science and Engineering. The instrument will be used to help characterize polymeric particles as well as inorganic nanoparticles and nanowires.
Yonsei University – Department of Materials Science and Engineering
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.
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.
Low-voltage transmission electron microscopy (LVTEM) of NaMMT particles with the biopanned phage clones qualitatively showed selective binding to the aluminosilicate layers (Figure 1). For example, the phage clone expressing M1 exhibited binding to the MMT sheets (Figure 1C), whereas the M13 phage displaying a non-specific peptide showed little or no binding to the MMT (Figure 1B).
Takeaway from Figure 1:
Drummy, L., Jones, S., Pandey, R., Farmer, B., Vaia, R., & Naik, R. (2010). Bioassembled Layered Silicate-Metal Nanoparticle Hybrids ACS Applied Materials & Interfaces, 2 (5), 1492-1498 DOI: 10.1021/am1001184
Led by Dr. Emilien Pelletier, the Institut des Sciences de la Mer de Rimouski at the Université du Québec à Rimouski has obtained an LVEM5 benchtop electron microscope to help them study the short-term and long-term effects of nano-materials on the marine environment.
Dr. Pelletier is the Canada Research Chair in Marine Ecotoxicology. The overall objective of the chair is to understand the impact of natural and anthropogenic stresses on the short-and long-term high-latitude coastal ecosystems to contribute to the conservation, protection and sustainable development of cold coastal marine resources.
One of the key focuses of the lab is to study nanotoxicology as it applies to cold coastal environments. This is an emerging discipline that incorporates studies on the environmental fate and toxic effects of nano-materials on human and marine species such as phytoplankton, bivalves and echinoderms.
Currently the researchers are using the LVEM5 in TEM, SEM and STEM modes to examine marine animals that have been exposed to various nano-materials to better understand how these materials are being absorbed and incorporated into their shells.
Selected Images
For more information on Dr. Pelletier’s work see (in French)
University of Michigan (Ann Arbor, MI)
We have found that the LVEM can provide high contrast images of a wide variety of samples, including dendrimers
We are excited to announce that a LVEM5 benchtop electron microscope, with TEM SEM and STEM imaging modes, has recently been installed at the University of Manchester in the UK. Dr. Paul O’Brien’s Research group will be using the LVEM5 to enhance their research of various nanomaterials.
Examples of materials
Dr. O’Brien’s research interests are mainly concerned with semiconducting nanomaterial and span interfacial areas of chemistry and materials science. The group is actively involved in precursor design and synthesis, Chemical vapour depositions, Chemical bath depositions, single source approaches to nanocrystals and interfacial deposition. Please see the POB Research Group’s website for more information.
Research Groups Website: (Click Here)The LVEM5 will be used by the AFRL HE at WPAFB to visualize nanoparticles of various scales in tissue and determine where the nanoparticles sequester in tissue sections.
The LVEM5 will be used by the NRCC-BRI for the characterization of NCC (nano-crystalline cellulose) fibers, NCC-based novel materials and a variety of nano-filaments and nanoparticles
