Nanoscopic observation of a gold nanoparticle-conjugated protein using near-field scanning optical microscopy

Techniques for physicochemical characterization of nanomaterials

Advances in nanotechnology have opened up a new era of diagnosis, prevention and treatment of diseases and traumatic injuries. Nanomaterials, including those with potential for clinical applications, possess novel physicochemical properties that have an impact on their physiological interactions, from the molecular level to the systemic level. There is a lack of standardized methodologies or regulatory protocols for detection or characterization of nanomaterials. This review summarizes the techniques that are commonly used to study the size, shape, surface properties, composition, purity and stability of nanomaterials, along with their advantages and disadvantages. At present there are no FDA guidelines that have been developed specifically for nanomaterial based formulations for diagnostic or therapeutic use. There is an urgent need for standardized protocols and procedures for the characterization of nanoparticles, especially those that are intended for use as theranostics.

Origin, separation and identification of environmental nanoparticles: a review

The biogeochemical and ecological impacts of environmental nanoparticles (ENPs) are some of the fastest growing areas of research today. However, efficient separation and collection of ENPs in natural systems remains difficult. This review article is focused on experimental investigation of separation and identification of ENPs, including nanoparticles with size fractions in the range of <2000, 450 to 2000, 100 to 450 and 1 to 100 nm. An automated ultrafiltration device (AUD) was used successfully to overcome the problem of efficiently collecting ENPs in large quantities in red soils. A significant amount of hematite nanoparticles was present on the surface coating of kaolinite nanoparticles and aggregated hematite nanoparticles overlapping the edge of a kaolinite flake in a size range of 5 to 8 nm. Synchrotron XRD technique is more straightforward and powerful than conventional XRD with oriented specimens and random powder methods for identifying nanoparticles, crystallinity, and particle size in red soils, particularly for the illite, kaolinite, goethite and hematite nanoparticles. The AUD apparatus can be employed to efficiently collect large quantities of soil and related ENPs for investigation of their structural characteristics and surface properties, which have significant impact on weathering reaction pathways, catalysis, the fate of vital elements and environmental pollutants, and ecosystem restoration.