Gold nanostars (GNSs) are promising contrast agents for simultaneous photothermal therapy and photoacoustic imaging (PAI) owing to their excellent photothermal conversion efficiency. However, GNSs are easily reshaped under transient high-intensity laser pulses, which can cause a rapid shift in the light absorption peak, resulting in a decrease in both therapeutic and monitoring effects. In this work, we synthesized GNSs without toxic surfactants and coated them with a silica shell to retain their shape, thus maintaining their photostability. The excellent performance of these silica-coated GNSs was verified through both in vitro and in vivo PAI experiments. The silica-coated GNSs exhibited a threefold improvement in photoacoustic stability, as compared with the non-coated GNSs. The proposed silica coating method for GNSs was found to improve the photostability of GNSs, making them efficient, safe, and reliable nanoparticles for PAI.

金纳米星（GNS）因其优异的光热转换效率而成为同步光热治疗和光声成像（PAI）的有前途的造影剂。然而，GNS 在瞬态高强度激光脉冲下很容易重塑，这会导致光吸收峰快速移动，导致治疗和监测效果下降。在这项工作中，我们合成了不含有毒表面活性剂的 GNS，并用二氧化硅壳包裹它们以保持其形状，从而保持其光稳定性。这些二氧化硅涂层的 GNS 的优异性能通过体外和体内PAI 实验得到验证。与未涂覆的 GNS 相比，涂覆二氧化硅的 GNS 的光声稳定性提高了三倍。研究发现，所提出的 GNS 二氧化硅涂层方法可以提高 GNS 的光稳定性，使其成为用于 PAI 的高效、安全和可靠的纳米颗粒。