With the continuous development of nanotechnology, gold nanoparticles are widely used in the field of medicine. Gold nanoparticles not only have good controllability, biocompatibility, and biosorption, but also have a high degree of stability, and can achieve specific biometrics and functions through surface modification. Therefore, it has become an important nanomaterial in biomedicine.

The Role of Gold Nanoparticles

Gold nanoparticles alias AuNPs and nano gold, their diameters are 1~100 nm. Gold nanoparticles are nano-sized particles of gold, and the powder is black or dark brown. The nano-gold solution is generally a sol dispersed in aqueous solution, so it is also called colloidal gold, water-soluble colloidal gold nanoparticles, and so on. The gold nanoparticles with different particle sizes show different colors. The color of colloidal gold is related to many factors. The colloidal gold with a small particle size (2-5nm) is yellow, the colloidal gold with a medium particle size (10-20nm) is wine red, and the colloidal gold with a larger particle size (30-80nm) is fuchsia. Gold nanoparticles have excellent properties such as localized surface plasmon resonance (SPR), conductivity, biocompatibility, small size effect, surface effect, quantum size effect, and macroscopic quantum tunneling effect. Gold nanoparticles have broad development prospects in the fields of catalysis, biomedicine, biosensors, electronics, optics, etc.

Medical Applications of Gold Nanoparticles

• Bioimaging

Bioimaging is a non-invasive diagnostic method, that can obtain information about tissues, organs, and pathological changes through the process of scanning, testing, and recording biological samples. Gold nanoparticles have a good application prospect in biological imaging, mainly in the following aspects:

1. Magnetic resonance imaging

Gold nanoparticles can provide high-contrast images, so they are an excellent contrast agent for MRI (magnetic resonance imaging). By modifying the surface of gold nanoparticles, targeted MRI imaging can be achieved, and the size or shape of nano gold can be adjusted according to different needs.

2. CT imaging

Gold nanoparticles also have good applications in CT (computed tomography) imaging. Because of its high atomic number, it can absorb X-rays and provide strong contrast images, so it is a contrast agent suitable for CT analysis.

3. Optical imaging

Due to the unique optical properties of gold nanoparticles, i.e., surface plasmon resonance, AuNPs can be readily used to enhance optical imaging based on their absorption, scattering, fluorescence, Raman scattering, etc.

• Drug delivery

The application of gold nanoparticles in drug delivery is one of its most prominent characteristics. Gold nanoparticles with large specific surface area and high stability can achieve effective drug loading and targeted transport in solution, so as to achieve more accurate, efficient, and safe drug therapy. Traditional drug therapy often has toxic side effects, and nanoparticles can reduce these side effects by changing the drug release rate, targeting, and immobilization. For example, they can be tailor-made to achieve both controlled drug release and disease-specific localization by tuning the polymer characteristics and surface chemistry. Studies have shown that AuNPs coated with polyethylene glycol (PEG) can reduce cytotoxicity, which means they can be used intravenously as carriers of DNA and drugs. PEG is amphiphilic in nature, which makes gold nanoparticles stable and monodisperse in aqueous biological environment. PEG can also prolong the cyclic half-life of AuNPs, thus allowing the reticuloendothelial system to uptake and remove nanoparticles.

• Biosensing

In terms of sensitivity and specificity, gold nanoparticles have become an important diagnostic tool, especially in the field of virology. Gold nanoparticle biosensors are mainly based on the detection of the energy flow on the surface of the particles, when the analyte interacts with it, the energy flow will change obviously. Gold nanorods are particularly useful in the generation of nanosensors.

Challenges and Future Prospects

Although gold nanoparticles are generally considered to be highly biocompatible, their biotoxicity is still a key issue. Size, shape, and surface modification may affect its toxicity. Ensuring the safety of gold nanoparticles is very important for medical applications. In addition, the mechanism of elimination and metabolism of gold nanoparticles in vivo is not completely clear. This may affect its circle time and effectiveness in the body. More research is needed to understand their behavior in the body. It is expensive to prepare high-quality gold nanoparticles, which will limit their application in the medical field. Finding a more cost-effective and greener method for the preparation of gold nanoparticles is an important challenge.

Despite these challenges and limitations, gold nanoparticles still have great potential in medical applications, and continuous research is looking for solutions to overcome these problems. With the development of science, we can expect to see more innovative medical applications using gold nanoparticles.

Accessing Gold Nanoparticles

CD Bioparticles is a leading manufacturer and supplier of gold nanoparticles, microparticles, and their specialized coatings. Our products find wide-ranging applications across various fields, including in vitro diagnostics, biochemistry, cell analysis, cell separation, and immune assays. Our commitment is to be a trusted source that meets all your needs for assay development and manufacturing.

References

1. Milan, J., Niemczyk, K., & Kus-Liśkiewicz, M. (2022). Treasure on the Earth—gold nanoparticles and their biomedical applications. Materials, 15(9), 3355.
2. Versiani, A. F., Andrade, L. M., Martins, E. M., Scalzo, S., Geraldo, J. M., Chaves, C. R., … & Da Fonseca, F. G. (2016). Gold nanoparticles and their applications in biomedicine. Future Virology, 11(4), 293-309.