Synthesis And Surface Modification Of Gold Nanorods And Its Application In Cancer Therapy

While gold nanorods have been extensively studied and used in manybiological, plasmonics, and sensing applications, their conventionalseed-mediated synthesis still presents a number of limitations. Its highsensitivity to the concentration of the reducing agent (ascorbic acid) leads toproblems with reliability as well as extremely poor yield of ionic-to-metallicgold conversion, which is below20%. In addition, the synthesis of high puritynanorods with longitudinal surface plasmon resonance (LSPR) peak higherthan1000nm is particularly difcult utilizing this technique. To deal with theproblems, in this paper, a novel method to prepare gold nanorods with highyield and uniform size by using phenols as reducing agents was developed.Surface modification of gold nanorods was investigated for improving itsdispersibility and biocompatibility. And gold nanorods were used ashyperthermia agents for cancer therapy. The main research contents are asfollows:(1) Preparation of gold nanorods using hydroquinone as a reducing agentin seeded method. The efect of changing various parameters includinghydroquinone, seed, and silver concentration was examined. The results showthat monodisperse gold nanorods with aspect ratio from1.5to7.3,longitudinal surface plasmon resonance tunable from550to1110nm anddimension (length×width) from90×13to30×4nm can be synthesized bycontrolling the experimental parameters.(2) Preparation of gold nanorods using hydroquinone,1,2,3-trihydroxyb-enzene, and1,2,4-trihydroxybenzene as reducing agents in seedless method.The efect of changing various parameters including sodium borohydridesilver concentration was examined. A detailed ICP-MS measurement of goldnanorods was conducted for analyzing the yield of ionic-to-metallic goldconversion of gold nanorods. The results show that monodisperse goldnanorods with longitudinal surface plasmon resonance tunable from550to1110nm and dimension (length×width) from57.8×13.1to111×45.2nm canbe synthesized by controlling the experimental parameters. The yield ofionic-to-metallic gold conversion of gold nanorods prepared by using phenolsas reducing agents in seedless method can be exceeding60%in all cases and even90%in some cases.(3) Surface modification of gold nanorods and its application in cancertherapy. The toxicity and specific absorption rate of gold nanorods wereassessed. The photothermal effect of gold nanorods for gastric cancer cell andsolid tumor was investigated. The results show that gold nanorods have gooddispersibility and low toxicity after modifying with carboxylated bovineserum albumin. Upon NIR laser irradiation (808nm,4W/cm2), gold nanorodscoated carboxylated bovine serum albumin have good inhibition on gastriccancer cells and mice solid tumor.