Gold Nanoparticles (AuNPs) were synthesized following a procedure described by Niu et. al. with slight modifications. An aqueous solution of 10 mL of 2.5 × 10 -4 M HAuCl4 was heated under stirring at 750 rpm to a temperature setpoint of 95 °C for the heating blocks which results in an internal temperature of the synthesis solution of approximately 75° C. After temperature stabilization for 5 minutes, 350 µL of an aqueous sodium citrate solution (10 mg/mL) were added at a rate of 10 mL/min. The reaction mixture changed to a wine-red color within several minutes indicating gold NP formation, which were ca. 16 nm in diameter and had an estimated concentration of approximately 9 × 10 11 NPs/mL, assuming all HAuCl4 was converted to NPs. The solution was cooled, and particles were purified by centrifugation (3500 rcf, 90 mins, 5 °C), then ultrasonically redispersed (5 s) in 10 mL of Milli-Q water.