Gold nanomatriaLs for Chemical Industry

Key Properties: 

 Strong SPR at ~520 nm; size 5–100 nm; highly stable 

Applications:

 Gold nanoparticles (AuNPs) in the 10–100 nm spherical range exhibit size-dependent optical, electronic, and surface properties that make them highly valuable across industrial and biomedical sectors.  

Key Properties: 

 Strong SPR at ~520 nm; size 5–100 nm; highly stable 

Applications:

 Gold nanoparticles (AuNPs) in the 10–100 nm spherical range exhibit size-dependent optical, electronic, and surface properties that make them highly valuable across industrial and biomedical sectors.  

Industrial Applications of Spherical AuNPs (10–100 nm)

1. Sensors (Chemical, Gas, Biosensors)

• Surface Plasmon Resonance (SPR) enhances signal in optical sensors.
• Used in colorimetric sensors for detecting heavy metals, explosives, or organic compounds (e.g., TNT).
• Electrochemical  sensors benefit from AuNPs' conductivity and surface reactivity.

2. Catalysis

• Act as efficient catalysts or catalyst supports in:
  • CO  oxidation
  • Selective hydrogenation
  • Green   chemistry reactions (e.g., reduction of nitrophenol)
• Catalytic activity is optimal for <20 nm size due to high surface area.

3. Electronics and Photonics

• AuNPs  used in conductive inks, transparent electrodes, and plasmonic   devices.
• Integration in flexible electronics and MEMS/NEMS     (micro/nanoelectromechanical systems).

4. Textile Industry

• Incorporated into fabrics for antibacterial and UV-protective textiles.
• Enables smart textiles for wearable sensors or color-changing garments.

5. Cosmetics

• Used in anti-aging creams and sunscreens due to their anti-inflammatory and      antioxidant properties.
• Act as delivery vehicles for active ingredients.

Biomedical Applications of Spherical AuNPs (10–100 nm)

1. Diagnostics

• Lateral flow assays (e.g., pregnancy test strips, COVID-19 test kits) use      20–40 nm AuNPs for red color indication.
• SPR-based  biosensors: AuNPs functionalized with antibodies/aptamers detect specific DNA, RNA, or protein markers.

2. Drug and Gene Delivery

• AuNPs are biocompatible carriers:
  • Functionalized with PEG, peptides, or aptamers to deliver anticancer drugs (e.g., doxorubicin).
  • Used for siRNA/miRNA delivery in gene silencing applications.
• 30–50 nm AuNPs are optimal for cellular uptake.

3. Photothermal Therapy (PTT)

• AuNPs absorb near-infrared (NIR) light and convert it to heat to selectively destroy      tumor cells.
• Spherical      AuNPs can be tuned near ~520 nm but can be aggregated or reshaped to      absorb in NIR.

4. Bioimaging and Contrast Agents

• Serve      as contrast enhancers in:
  • CT       imaging
  • Photoacoustic       imaging
  • Multiphoton       microscopy
• Easily      functionalized for targeted imaging (e.g., tumor or vascular      tissues).

5. Antibacterial and Wound Healing

• AuNPs      (~10–30 nm) disrupt bacterial membranes and inhibit growth.
• Used      in antimicrobial wound dressings or hydrogels.

6. Cancer Theranostics

• Combine      diagnosis and therapy in a single platform:
  • Detect       tumor via imaging
  • Deliver       drug or heat (PTT)
  • Monitor       therapeutic response

Key Properties:

 Tunable longitudinal SPR (650–900 nm); high aspect ratio   

Applications:

Gold nanorods (AuNRs) in the 10–100 nm size range have anisotropic shapes and tunable longitudinal surface plasmon resonance (LSPR) in the visible to near-infrared (NIR) region (600–1200 nm), which sets them apart from spherical gold nanoparticles.

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Key Properties:

 Tunable longitudinal SPR (650–900 nm); high aspect ratio   

Applications:

Gold nanorods (AuNRs) in the 10–100 nm size range have anisotropic shapes and tunable longitudinal surface plasmon resonance (LSPR) in the visible to near-infrared (NIR) region (600–1200 nm), which sets them apart from spherical gold nanoparticles.

This tunability, combined with biocompatibility and surface functionalization capability, leads to numerous specific industrial and biomedical applications.

Industrial Applications of Gold Nanorods (10–100 nm)

1. Optoelectronic Devices

• Plasmonic photodetectors and solar cells:
  • AuNRs with LSPR in the visible/NIR range improve light absorption efficiency.
  • Enhance photoelectric conversion in thin-film solar technologies.

2. Optical Data Storage & Displays

• Used in multilayer optical storage and color-tunable reflective displays, leveraging their size- and aspect-ratio-dependent scattering properties.

3. Nanoantennae and Metamaterials

• AuNRs function as optical nanoantennae, capable of focusing light at the      nanoscale.
• Utilized in plasmonic metamaterials for light manipulation and cloaking materials.

4. Catalysis (Enhanced)

• Though less used than spherical AuNPs, nanorods offer facet-selective catalysis in:
  • Hydrosilylation
  • Reduction reactions
  • Plasmon-driven       photocatalysis

5. Chemical and Environmental Sensing

• Functionalized AuNRs are used in refractive index-based sensing (e.g., gas or pH sensors).
• LSPR shifts with changes in the surrounding dielectric environment.

Biomedical Applications of Gold Nanorods (10–100 nm)

1. Photothermal Therapy (PTT)

• Most  prominent application:
  • AuNRs absorb NIR light (~700–900 nm) and convert it to localized heat.
  • Used to ablate tumor cells with minimal damage to healthy tissues.
  • Sizes  ~40 × 10 nm to 60 × 15 nm with aspect ratios 3–4 are ideal for deep tissue penetration (NIR-I window).

2. Photoacoustic Imaging

• AuNRs enhance photoacoustic contrast due to strong NIR absorption.
• Ideal for non-invasive deep tissue imaging in cancer, cardiovascular, and      brain disorders.

3. Targeted Drug and Gene Delivery

• Functionalized AuNRs can deliver:
  • siRNA/DNA
  • Small molecule drugs
  • Controlled release triggered by NIR light (on-demand delivery).
• Coated with PEG, antibodies, or aptamers for tumor targeting.

4. Theranostics

• Combined      diagnosis and therapy in a single particle:
  • NIR imaging + drug delivery + photothermal therapy.
  • AuNRs are often conjugated with contrast agents (e.g., fluorophores or MRI labels).

5. Surface-Enhanced Raman Scattering (SERS)

• AuNRs provide strong electromagnetic field enhancement at tips.
• Functionalized with Raman reporters for ultrasensitive detection of biomolecules,      pathogens, or cancer markers.

6. Cell Tracking and Labeling

• Bioconjugated AuNRs (e.g., with folate, RGD peptides) are used for live-cell labeling     and tracking migration patterns under microscopy.

7. Antibacterial Photothermal Applications

• AuNRs irradiated with NIR light generate heat sufficient to kill      multidrug-resistant bacteria without antibiotics.
• Used in wound healing patches and catheter coatings.