Control in the Shell Uniformity of Gold Nanorod@Silica Core-shell Nanoparticles and Its Effect in the Core Melting

• Main Authors: Lin, Chia-Yu, 林珈瑜
• Other Authors: Wang, Churng-Ren Chris
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/89848666093848408844

碩士 === 國立中正大學 === 化學暨生物化學研究所 === 100 === There are many literature about the structure of core-shell AuNP@silica, but only uniform thickness of silica was reported (AuNR@u-silica). Our lab had a technique to synthesize gold nanorod coated with non-uniform silica shell (AuNR@nu-silica), which was reported that can enhance photoacoustic imagine. We suspected that the signal enhancement was caused by anisotropic heat flux. Simultaneous, we didn’t understand the main reason which affect the uniformity of shell coating. So, there are two goals in my research, the first goal is to find the controlling parameters in the uniformity of shell and to control their thickness, then to conduct the kinetic studies. The second goal is to search for the new evidence of the anisotropic flux. Therefore, this thesis contains three parts: in the first part, we found that the main factor which affect uniformity is pH value. At lower pH(=8), the shell growth rate(r) of long-axis thickness(LT) is much different with short-axis thickness(ST). In the inition, r(ST) = 6 nm/hr and r(LT) = 0 nm/hr, then we can get non-uniform coating. At higher pH(= 9), r(ST) is similar with r(LT), the value are 9 nm/hr and 6 nm/hr. Then we can get uniform coating. Afterward, we can control the shell thickness from 0 nm to 15 nm of two type AuNR@silica. The second part of this thesis, we got a new indirection evidence of the anisotropic flux by laser-induced gold nanorods melting. According to our experiment result, the heat flux of AuNR@u-silica is similar at long-axis and short-axis, so the shape transformation is from rod to 1-sphere or short-rod. The amount of shape transformation is about 76%. In the case of AuNR@nu-silica, because the difference of LT and ST, the anisotropic flux is difference, too. The shape transformation is from rod to 2-sphere and the amount of shape transformation is about 66%. At the third part, we collaboration with other team to develop a novel technique which use AuNR for quantitatively monitoring focused-ultrasound induced blood-brain barrier (BBB) opening in a rat model. We conjugate mPEG-SH onto AuNR surface to as a contrast agent. Our goal is to confirm the nanoprobe conform two requirements. One is the nanoprobe maintain the characteristic absorption property arising from the surface plasmon of AuNR satisfies the application need. And second condition is preservation in both shape and dispersity of AuNRs.