Cup horn sonotrode

AuNDs were synthesized using an emulsion method, and AuMBs were synthesized as described previously7 . The synthesis of AuNDs involved premixing AuNRs with an absorption peak at 808 nm and ice-cold liquid C₅F₁₂ with a low boiling point of 29 °C in 20% HSA (Octapharma, Switzerland) in a glass bottle, and then exposing the mixture to ultrasound by a digital sonicator with a cup-horn sonotrode (Branson, USA). The solution was exposed to three cycles of 5-minute sonication at room temperature followed by 5 minutes of rest on ice. After centrifugation at 1800 rpm for 3 minutes twice, AuNDs with diameters of 300 ~ 500 nm were isolated. The size of the AuNDs was accurately measured using two devices: a Coulter MultiSizer III (Beckman Coulter, USA) and a Zetasizer Nano ZS (Malvern Instruments, UK).

The main components of AuNDs were gold nanorods (AuNRs), with longitudinal plasmon resonance wavelength at 808 nm, PFP (C₅F₁₂), and 20% human serum albumin solution (Octapharma AG, Lachen, Switzerland). The AuNDs were synthesized as reported in our previous work [26 (link)]. In brief, the three components were mixed in 1 mL of phosphate-buffered saline (PBS, purchased from Gibco, Thermo Fisher Scientific, Waltham, MA, USA) followed by sonication using a digital sonifier (Branson, Danbury, CT, USA) with a cup-horn sonotrode (Branson, Danbury, CT, USA). After 4 cycles of 5-min sonication and 5-min rest on ice, the droplet emulsions were formed. The sedimentary droplet emulsions were then resuspended in 1 mL of PBS and then centrifuged at 1700 rpm for 3 min for three times at 4 °C to isolate the nano-sized droplets. After centrifugation, the supernatant was further analyzed by using Coulter MultiSizer III (Beckman-Coulter, Hamburg, Germany) and Zetasizer (Nano Z, Worcestershire, UK) to count the number of the droplets and measure the size distribution, respectively. AuNDs with a size ranged from 200 to 500 nm were then applied for the following experiments.