**Shape-Controlled Synthesis of Au Nanostructures Using EDTA Tetrasodium Salt and Their Photothermal Therapy Applications**

### **Youngjin Jang 1, Nohyun Lee 2, Jeong Hyun Kim 3, Yong Il Park 4,\* and Yuanzhe Piao 5,\***


Received: 27 March 2018; Accepted: 16 April 2018; Published: 18 April 2018

**Abstract:** Tuning the optical properties of Au nanostructures is of paramount importance for scientific interest and has a wide variety of applications. Since the surface plasmon resonance properties of Au nanostructures can be readily adjusted by changing their shape, many approaches for preparing Au nanostructures with various shapes have been reported to date. However, complicated steps or the addition of several reagents would be required to achieve shape control of Au nanostructures. The present work describes a facile and effective shape-controlled synthesis of Au nanostructures and their photothermal therapy applications. The preparation procedure involved the reaction of HAuCl4 and ethylenediaminetetraacetic acid (EDTA) tetrasodium salt, which acted as a reducing agen<sup>t</sup> and ligand, at room temperature without the need for any toxic reagen<sup>t</sup> or additives. The morphology control from spheres to branched forms and nanowire networks was easily achieved by varying the EDTA concentration. Detailed investigations revealed that the four carboxylic groups of the EDTA tetrasodium salt are essential for effective growth and stabilization. The produced Au nanowire networks exhibited a broad absorption band in the near-infrared (NIR) region, thereby showing efficient cancer therapeutic performance by inducing the selective photothermal destruction of cancerous glioblastoma cells (U87MG) under NIR irradiation.

**Keywords:** gold; nanostructure; EDTA tetrasodium salt; photothermal therapy
