Photostability enhancement of silica-coated gold nanostars for photoacoustic imaging guided photothermal therapy

Photoacoustics, 2021 · DOI: https://doi.org/10.1016/j.pacs.2021.100284 · Published: July 17, 2021

Simple Explanation

Gold nanostars (GNSs) are promising for photothermal therapy and photoacoustic imaging, but they easily change shape under high-intensity laser pulses, reducing their effectiveness. To solve this problem, we synthesized GNSs and coated them with a silica shell to help them maintain their shape. The silica-coated GNSs showed a threefold improvement in photoacoustic stability compared to uncoated GNSs. This enhancement ensures they remain effective, safe, and reliable for photoacoustic imaging. Silica coating affords three main advantages. First, synthesis methods for silica coating are mature and reproducible even at the mass production level. Second, an ideal and permanent attachment between biomarkers and GNPs can be achieved through the covalent coupling of biomolecules to the surface-functionalized silica coating.

Study Duration

Not specified

Participants

Tumor-bearing nude mice

Evidence Level

In vitro and in vivo experiments

Key Findings

1
Silica-coated GNSs exhibit a threefold improvement in photoacoustic stability compared to uncoated GNSs, making them more reliable for PAI.
2
An optimized silica shell thickness of 25 nm provides the best balance between stability, safety, and dispersion of GNSs.
3
The cytotoxicity test results show that silica-coated GNSs are biocompatible with MSCs, with cell survival rates above 80% at tested concentrations.

Research Summary

This study focuses on enhancing the photostability of gold nanostars (GNSs) by coating them with silica shells for improved performance in photoacoustic imaging (PAI) and photothermal therapy (PTT). The researchers found that a 25 nm-thick silica coating provides an optimal balance between stability, safety, and dispersion, leading to a threefold increase in PA stability compared to uncoated GNSs. In vitro and in vivo experiments confirmed the enhanced PA stability of the silica-coated GNSs, demonstrating their potential for longer-term PAI monitoring and improved PTT efficiency.

Practical Implications

Improved PAI Monitoring

The enhanced photostability allows for longer and more reliable monitoring during photoacoustic imaging.

Enhanced PTT Efficiency

The silica coating can be functionalized to promote GNS accumulation in tumors, increasing the efficiency of photothermal therapy.

Clinical Translation Potential

The use of biocompatible materials and the ability to trace these materials in the body enhance the potential for clinical application, especially with the confirmation of in vivo safety.

Study Limitations

1
Further research is needed to establish a physical model for silica-coated GNSs to optimize the silica coating thickness and strengthen the PA and photothermal effects.
2
The effect of the size of silica-coated GNSs on cellular uptake and metabolism needs to be considered for potential in vivo applications.
3
Unified testing standards for nanoparticles are needed to facilitate the clinical translation of these materials.

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