消光式核壳二聚体传感器的设计与光谱特性分析

根据ITO/Au纳米核壳二聚体粒子在生物医学领域的应用合理性,设计了一种实时检测生物液体的核壳二聚体探针消光式传感器;由偶极子理论推导出输出波长与外界环境折射率关系;利用MATLAB设计ITO/Au纳米核壳二聚体粒子结构;采用软件DDSCAT7.3结合离散偶极近似法,利用二聚体有效半径模拟计算了300~950nm可见光到红外光波段不同核壳比、二聚体间距、以及不同介质折射率的消光光谱;根据传感芯片折射率与偶极共振、耦合八级共振的响应关系得出ITO/Au二聚体的折射率灵敏特性。与传统Ag/Au核壳纳米粒子相比,ITO/Au纳米核壳二聚体结构引入了可作为传感芯片灵敏性自参考参数的耦合八级共振峰,同时ITO/Au二聚体结构的折射率灵敏度可达到419nm/RIU。这些工作及其结果对制作消光式传感器具有重要的意义。

Design and spectral analysis of extinction core-shell dimer sensor

Based on the rationality of applications of ITO/Au core-shell dimer nanoparticles in the biomedical field, an extinction type sensor of core-shell dimer probe for the real-time detection of biological liquid was designed. The relationship between the output wavelength and the refractive index of the external environment was deduced from the dipole theory. And MATLAB was used to design the structure of the ITO/Au core-shell dimer nanoparticle. By adopting the DDSCAT7.3 software in combination with the discrete dipole approximation method, and using the effective radius of the dimer, the 300~950 nm extinction spectra from the visible to the infrared band were simulated for different values of core-shell ratio, dimer spacing and refractive index. Also, the refractive index sensitivity of ITO/Au dimers was obtained according to the response relationship between the refractive index of the sensing chip and the dipole and coupled octupole resonances. Compared to traditional Ag/Au core-shell nanoparticles, the ITO/Au core-shell dimer nanoparticle structure introduced the coupled octupole resonance peaks which could be used as the self-reference parameter of sensitivity for the sensing chip. In the meantime, the refractive index sensitivity of ITO/Au dimer structure could reach 419 nm/RIU. These work and results are of great significance for the fabrication of extinction type sensors.