ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Highly branched and hollow gold nanourchins for bacterial killing and off-resonance SERS sensing

Nhung Thi Tran, Tien-Giang Nguyen, Minh-Tam Le, Khanh-Son Trinh, Viet-Duc Phung, Anh-Tuan Nguyen Huynh, and Nam-Thang Pham

Ho Chi Minh City University of Technology and Education, Ho Chi Minh City, Vietnam

E-mail: nhungtt@hcmute.edu.vn

Received: 18 May 2023  Accepted: 28 August 2023

Abstract:

Herein, we systematically investigated the synthesis of hollow gold nanourchins characterized by multiple sharp tips with extremely small radii of 5–10 nm radiating from central cores. The two-step-based approach was exploited to produce hollow Au nanourchins. The pre-synthesized Ag nanospheres were used as sacrificial templates in the galvanic replacement with HAuCl₄ precursor to assist the formation of hollow cores. Subsequently, ascorbic acid was added to trigger the co-reduction reactions to promote the growth of multiple sharp tips. The hollow Au nanourchins exhibit tunable morphology and optical response in the visible to near-infrared regions (725–1040 nm), simply by adjusting different reaction parameters, including the amounts of Ag seed, HAuCl₄ precursor, and ascorbic acid. Notably, the hollow Au nanourchins demonstrate a remarkably potent bactericidal efficiency against E. coli, surpassing that of spiky Au nanoparticles with solid cores. A better antibacterial activities were also observed for hollow Au nanourchins with shorter tips as compared to those with longer tips. Furthermore, the synthesized particles display a significant SERS enhancement toward the detection of Rhodamine B (10⁻⁴ M) even under off-resonance conditions. These findings highlight the potential of the hollow Au nanourchins as multifunctional materials for sensing and biological applications.

Keywords: Hollow Au nanourchins; Bactericidal efficiency; Wide spectral tunability; Off-resonance SERS

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-023-03077-8

Chemical Papers 77 (12) 7505–7514 (2023)