Size-Tunable Yolk–Shell Gold–Silver Nanostructures for Photothermal Treatment of Multidrug-Resistant Bacteria

Abstract

Framelike nanostructures consisting of interconnected, ultrathin ridges have attracted wide attention due to their high atomic utilization efficiency among typical hollow architectures but are yet to be comprehensively studied for photothermal applications. Herein, we report a facile synthesis of AuAg yolk–shell cubic nanoframes (YSCNFs) with tunable edge lengths, followed by the exploration of their photothermal conversion and in vitro bacteria-killing performance, together with our endeavors to understand the mechanism fundamentally. By adopting the rationally screened capping agent docosyltrimethylammonium chloride (DCTAC) throughout the stepwise synthesis, sharp cubic edges could be generated and largely reserved, leaving the 5 nm cubic nanoframes well standing. The increase in the cubic edge length leads to the red shift of the major LSPR absorption peak toward the NIR region, and abundant hot-spots appear at the frame corner and core surface according to finite-difference time-domain (FDTD) simulation. The photothermal conversion efficiency of YSCNFs can reach as high as 65.6% when a very low power density of 0.27 W cm–2 is used, which displays a powerful ability in combating multidrug-resistant bacteria. The present study offers a systematic investigation of bimetallic yolk–shell nanoframes including size/morphology control, photothermal properties, mechanism studies, and antibacterial applications, which could be of great value for the rational design of high-efficiency photothermal nanomaterials for services to biomedicine.

Thiosulfate-mediated seeded growth of Au@AuAg yolk–shell nanocubes with surface concavity: optical and catalytic properties

“…S1†) were generated according to the protocol as described in our previous study. 29 Then, they were reacted with HAuCl 4 via the GRR. Unlike the common GRR process reported in literature, we emphasized the use of sodium thiosulfate in the current case to mediate the GRR process.…”

Seeded Growth of Size-Tunable Au@Ag Core–Shell Nano-Octahedra and Their Yolk–Shell Derivatives for Near Infrared Photothermal Conversion

“…Stock solution containing Au@Ag core–shell nanocubes were prepared using the method as delineated in our previous research. − To obtain Au@Ag core–shell nano-octahedra, aqueous solutions of AA (20 mM, 1 mL), Cys (0.2 mM, 1 mL), and AgNO 3 (4 mM, 1 mL) were sequentially added to the as-prepared reaction mixture and kept at 60 °C for 2 h (P2 procedure). The whole solution was centrifuged once and redispersed in 1 mL of water, followed by the addition of OTAB (20 mM, 3 mL) and HAuCl 4 (0.5 mM, 1 mL) to conduct the oxidative carving (P3 procedure) at 60 °C for 1 h. Information on chemicals and materials used in the synthetic process is detailed in the Supporting Information.…”

Nanoframes as a Resilient Candidate for the Solution of Broader Spectra of Catalysis Challenges

“…When no laser irradiations were used, huge amounts of bacteria were found on the plate in the absence of these yolk-shell nanoframes. [134]However, by increasing the concentration of AgAuYSCNFs, the antibacterial efficiency was also increased (Figure 51A). Moreover, with increase in temperature photothermal performance was increased.…”