Gold Nanoparticles Applications in the field of Optical Imaging and Biology

Gold nanoparticles can be easily used for providing contrast in various different biological applications. Let's go over some such gold nanoparticles' applications below:

Gold nanoparticles applications in optoacoustic or photoacoustic imaging

Optoacoustic imaging technology is about a hybrid optical imaging method that involves combination of optics and acoustics. In this technique, laser light of a certain wavelength is used for illuminating the tissue. It leads to absorption of light by the tissue and its subsequent heating up, leading to thermoelastic expansion and omission of an acoustic wave. An ultrasound transducer detects this wave and generates an image.

How gold nanoparticles' applications are relevant in this regard are that the specificity and sensitivity of the photoacoustic imaging can be significantly enhanced with the use of contrast agents like gold nanoparticles.

Gold nanoparticles applications in OCT

Optical coherence tomography or OCT is an optical imaging technique that makes use of near-infrared light for penetrating into the scattered media such as biological tissue, and subsequent generation of 3-dimensional images with the help of an interferometric method. Optical coherence tomography is extensively used in the field of diagnostic medicine, most notably in interventional cardiology and ophthalmology.

How gold nanoparticles' applications are relevant here is that these nanoparticles are capable of scattering and absorbing near-infrared light, and function as good contrast agents for the OCT. They enable researchers to not just get a visual outlook of the anatomy, but in probing of the molecular targets inside the diseased tissue as well.

Lateral Flow Assays and gold nanoparticles

Lateral flow assay is a basic method of detecting the absence or presence of an analyte. Such tests are pretty commonly used in the field of medical diagnostics, laboratories or in diagnostic medical applications.

These lateral flow tests are mostly colorimetric assays for the purpose of doing away with the costly/specialized equipment for the readouts. How gold nanoparticles' applications find their way in this field can be shown by one of the many simple examples, for instance, the home pregnancy test in which gold nanoparticles are used for forming a well-evident pink link upon detection of the pregnancy marker - hCG or human chorionic gonadotropin.

Gold nanoparticles can be easily combined with the biomarkers, and employed in such immunochromatographic lateral flow tests. Furthermore, certain highly mono disperse gold nanoparticles can be specially designed for the purpose of lateral flow tests, and can help in improvement of the lateral flow reproducibility and sensitivity.

Reflectance Confocal Microscopy

The field of confocal microscopy is well known for the way in which one can acquire in-focus images from the selected depths using a method referred to as optical sectioning. It allows for the 3-dimensional reconstructions of the complex objects.

The reflectance confocal microscopy is finding clinical application in visualization of the skin lesions in a non-invasive way. It can even be employed in the study of ex vivo tissues or histological sections without having to opt for preservation procedures or complex preparation.

Gold nanoparticles can be employed as the bright contrast agents for the different reflectance confocal microscopy applications since they have large scattering cross sections. These applications can be both in ex vivo and in vitro settings.

That was about few gold nanoparticles' applications in the field of optical imaging and biology. Some of their other similar applications are in:

  • Photothermal therapy
  • Multimodal imaging
  • SERS or Surface Enhanced Raman Spectroscopy
  • Catalytic reactions
  • Conjugation with the fluorescent dyes in optical imaging
  • Sensor technologies and photonics
  • Therapeutic agent delivery and more