Applications of Gold Nanoparticles

 

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Applications of Gold Nanoparticles

With the advancement of technology and the continuous development of technical means, the applications of gold nanoparticles are more due to the unique chemical, optical, physical properties of gold nanoparticles,the more convenient preparation methods and diverse surface modification methods. The wider the properties, the wider the field involved.

Application in surface enhanced Raman spectroscopy

According to the characteristics of the surface plasmon absorption of gold nanoparticles, it can be regarded as a beam of electrons passing over the surface of the metal, thereby generating an enhanced electromagnetic field at or near the surface of the metal. Any molecule within this range of gold nanoparticle surfaces will be attracted to this powerful electromagnetic field. Based on this principle, surface enhancement spectroscopy was developed.

Application in photonic devices

Gold nanoparticles have a strong three-stage nonlinear sensitivity and a near-resonance nonlinear response. Therefore, it has an important use in nonlinear optical devices such as optical information processing and laser protection. The gold nanoparticles are implanted into a glass carrier and can be used to prepare nonlinear optical devices. In addition, the injection of gold nanoparticles into, for example, silicon pores, thiol complexes, and polymer supports, produces different nonlinear optical properties that can be used to fabricate nonlinear optical devices.

Application in catalysis

Since gold nanoparticles have good activity, they are often supported on other substances as catalysts for certain chemical reactions. Silver nanoparticles can also be used to replace common catalysts. Compared with other metal catalysts, gold nanoparticles have the following characteristics as catalysts:

  • The catalytic performance varies with the preparation method, and the size distribution of the particles, the particle size, the type of the carrier, and the interaction with the carrier may affect the catalytic performance;
  • The apparent activation energy of the catalyst is extremely small, generally less than 40kJ/mol, and thus is more suitable for low temperature catalyzed chemical reactions.

 

Application in bioelectrochemical sensors

  • Application in electrochemical protein sensors

The bioelectrochemical sensor can be constructed by direct electron transfer between the protein and the electrode using the mechanism of the biological redox process. However, if a protein having redox properties is directly in contact with the exposed surface of the metal, it causes a change in the structure and function of the protein, causing it to lose activity and inhibit electron transfer of the protein on the electrode.

It has been found that the orderly assembly of gold nanoparticles on the surface of metal solids can be carried out without the addition of electron donors or promoters, so as to maintain the biological activity of biomolecules such as proteins on the surface of metal solids. It is important to promote direct electron transfer of proteins for redox and electron transfer between substrates.

  • Application in electrochemical DNA sensors

The DNA electrochemical sensor is based on the basic principle of base pairing, and combines an electrode with a DNA probe immobilized with an electroactive indicator for detection. It has high sensitivity and can specifically identify organisms. It is applied to the diagnosis, detection and environmental monitoring and analysis of genetic diseases. The small size effect, surface effect and quantum size effect of gold nanoparticles and good biocompatibility are easy to bind to DNA molecules, so they become particles that are often biomarked in DNA sensors, which effectively improves the sensitivity of DNA biosensors.

  • Application in electrochemical immunosensors

Electrochemical immunosensors are an analytical technique for monitoring antigen-antibody reactions by combining specific immune responses with highly sensitive sensing techniques based on the principle of specific binding of antibodies and antigens. The use of gold nanoparticles to construct an electrochemical immunosensor port can effectively improve the biocompatibility and electron transfer rate of the electrode surface, and improve the sensitivity of detection and the width of the linear range.

  • Application in targeted diagnosis and treatment of tumors

To be applied to the targeted diagnosis and treatment of tumors, how to obtain multifunctional nanoparticles is the first step. Gold nanoparticles have good bioaffinity and unique surface properties, and surface-modified gold nanoparticles are linked to targeting molecules or drugs by covalent or non-covalent attachment. Gold nanoparticles are a good targeted preparation, which allows gold nanocarriers to be selectively distributed in tumor tissues, which can increase drug efficacy and reduce system side effects. In addition, after the surface modification of the gold nanoparticles, the target molecules can be used to achieve active targeting of the tumor, and the drug or the radiation is specifically brought to the tumor site to achieve the purpose of tumor targeted diagnosis and treatment.

Based on the above characteristics, gold nanometers have shown great potential in basic research to clinical transformation. The following are specific applications of gold nanoparticles in lung cancer research (Gold nanoprobes are used for detection of tumor markers in serum lung cancer)

  • Photoacoustic imaging PAT
  • Targeted drug delivery systems
  • Radiotherapy sensitization
  • Photothermal therapy

Challenges and development prospects

Gold nanoparticles have achieved certain results in many fields, but they also face research bottlenecks and huge challenges:

  • How to combine the research of gold nanoparticles with green chemistry?
  • How to reduce the cost of gold nano surface modification and find more abundant and multi-surface modifiers?
  • How to combine gold nanoparticles with the hottest biomedicine currently researched?

These questions are left to the reader to think about and explore!

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