Researchers Discovers a New Technique Using Magnetic Fields to Align Gold Nanorods for Better Imaging Performance

An international team of scientists developed a new technique using magnetic fields to align gold nanorods while still preserving their optical properties, Phys.org reported

Corresponding author Joe Tracy, a professor of materials science and engineering at North Carolina State University, said that scientists are interested in gold nanorods because they make suitable materials for biomedical imaging, sensors, and other technologies.

Magnetic Alignment of Gold Nanorods

Gold nanorods are of interest because they absorb and scatter specific wavelengths of light, making them more attractive materials for different technologies. Researchers noted that aligning them would cause polarization-dependent extinction and using magnetic fields could make it possible to control further and modulate which wavelengths they will respond to.

According to Tracy, if the alignment of gold nanorods can be controlled, there is a higher chance of retaining their optical properties without actually touching them to make better technologies for imaging, diagnostic, and therapy.

In their study titled "Magnetic Alignment for Plasmonic Control of Gold Nanorods Coated with Iron Oxide Nanoparticles," published in the journal Advanced Materials, the team discussed a new technique to align gold nanorods using magnetic fields.

The team synthesizes different solutions of gold nanorods and iron oxide nanoparticles and mixes them in which the latter floats to the surface of the former. It resulted in coated nanorods that can be controlled using a low-strength magnetic field, Phys.org reported.

Tracy and his team characterized the process and how well it works. They also successfully demonstrated how to align the nanorods without adversely affecting the optical properties of the gold nanorods.

Study first author Mehedi Rizvi thinks that those nanorods have the smallest aspect ratio of any elongated nanoparticle coated with iron oxide nanoparticles and align using magnetic fields. He noted that the team needed to optimize many aspects of the system, like the dimensions, size, and concentrations of the two solutions, for the technique to work.

For now, Tracy and his team are in the process of exploring potential applications of their magnetic-overcoated gold nanorods in imaging based on their multifunctional properties.

Gold Nanoparticles in Medicine

Nanotechnology has been a trending area of science in the past years and has made significant advances in developing functional engineered nanoparticles.

According to a paper in Frontiers in Bioengineering and Biotechnology, various nanoparticles have already been used in medical applications. One of these nanoparticles is the gold nanoparticles (AuNPs), which are widely used because of their unique functional properties and easy synthesis, attracting many scientists to explore them.

In medicine, they are used in drug and gene delivery, photothermal therapy (PTT), photodynamic therapy (PDT), radiation therapy, diagnoses, X-ray imaging, computed tomography (CT) scan, and other biological technologies and activities. Improving them will also be beneficial for biological and medical applications.

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