2.2. Animal Experiments and Injections

Female 8-week-old NU/NU (Crl:NU-Foxn1^nu) nude mice (Charles River Laboratories, Wilmington, MA, USA) were used for all imaging studies. Intravenous injections of gold nanoparticles consisted of particles in 100 µL volume. To evaluate particle concentration and pharmacokinetics in vivo, mice were injected with a bolus dose via tail vain injection through a catheter. Following the injection, catheter lines were flushed with additional PBS in order to ensure the full dose was administered. All procedures performed on the animals were approved by the University’s Institutional Animal Care and Use Committee (IACUC #20847) and were within the guidelines of humane care of laboratory animals.