Analysis of Nanoparticle Coatings

Topics Covered

Concept of NanoTweezer
Waveguide Measurements
Key Advantages of NanoTweezer
About Optofluidics Incorporated


Surface properties of a particle gain more significance with a decrease in particle size. At the nano scale, the surface properties of a particle influence its behavior such as aggregation, the ability to bind to the surface of a glass container, the ability to reach an epithelial cell, its efficacy at a tumor site, or the ability to build up a protein layer on its exterior.

Nevertheless, the state of the surface of a nanoparticle cannot be accurately determined by any of the available techniques. The widespread adoption of nanoparticles in many different areas, including household products, batteries, electronics, and medicine, compels the availability of an enhanced analytical method. The NanoTweezer instrument from Optofluidics has revolutionized the analysis of nanoparticle surfaces and enables gaining insights into interfacial forces.

Concept of NanoTweezer

Gaining insights into surface properties is crucial to produce nanoparticle dispersions with colloidal and chemical stability. The NanoTweezer provides an improved analysis technique for nanoparticle surfaces based on a simple concept. The system determines the amount of energy required to push a nanoparticle down onto a surface as well-stabilized particles are repulsive in nature otherwise they would form aggregation.

The particles will also get repelled from any surface that imitates their own, making them difficult to push down onto the surface. Conversely, pushing poorly stabilized particles down onto a surface will be easier. This concept is applicable for any particle surface interaction, including electrostatic, steric, and hydrophilic.

Waveguide Measurements

Optofluidics uses its innovative waveguide-based technology in the NanoTweezer. This unique technology pushes nanoparticles across the waveguide surface using a laser and quantifies the surface interactions the waveguide and the nanoparticle (Figure 1). Special coatings can be applied to tune the waveguide surface based on what surface interaction is significant.

Figure 1. The concept of the NanoTweezer

The intensity histograms of each particle enable determining potential wells. The optical component is removed from the potential well to provide surface energy plots. In this illustration (Figure 2), a relatively small amount of energy is required by the particle to obtain about 80nm from the surface (red arrow). Beyond this point, a high level of energy is needed to “push” the nanoparticles closer.

Figure 2. For this particular case, the particle required relatively little energy to get about 80 nm from the surface (red arrow). After this point, much more energy is required to “push” the particle closer.

Key Advantages of NanoTweezer

The following are the key benefits of the NanoTweezer:

  • Can measure surface properties of individual particles
  • Capable of analyzing a variety of surface interactions (charged, steric, etc.)
  • Operates in the native environment of the particle
  • Measurement sensitivity in the piconewton range
  • Capable of handling many different types of particle materials
  • Capable of operating on a particle range of 50nm up to 2µm

About Optofluidics Incorporated

Optofluidics, Inc. is a venture backed life-sciences company that is developing microfluidic and biophotonic nanomanipulation technologies for biological, material science, and pharmaceutical applications.

Our investors and development partners include BioAdvance, the National Science Foundation, the Defense Advanced Research Projects Agency, and the Ben Franklin NanoTechnology Institute.

In 2012 Optofluidics was named Philadelphia Life Sciences startup of the year.

This information has been sourced, reviewed and adapted from materials provided by Optofluidics Incorporated.

For more information on this source, please visit Optofluidics Incorporated.

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