90 plus particle sizer analyzer

The GNPs were synthesized via the reduction of HAuCl₄ by sodium citrate, which is more commonly referred to as the Turkevitch method [29 (link)]. By varying the amount of sodium citrate, the method can yield NPs of varying sizes. In this study, 20-nm particles were chosen since our future goal is to use these NPs for gene delivery. The GNPs were characterized by transmission electron microscopy (H7000; Hitachi Corp. Tokyo, Japan), UV-spectroscopy (Lambda 40; PerkinElmer, Waltham, MA), and by dynamic light scattering using 90 Plus Particle Sizer Analyzer (Brookhaven Instruments Corp. New York, NY) to determine the size of the particles.

Gold nanoparticles were synthesized using the citrate reduction method [53 (link)]. First, 300 μL of 1% chloroauric acid (HAuCl₄·3H₂O) (Sigma-Aldrich, Oakville, ON, Canada) was added to 30 mL of double–distilled water and heated on a hot plate while stirring. Once it reached the boiling point, 1 mL of 1% sodium citrate tribasic dehydrate (HOC(COONa)(CH₂COONa)₂·2H₂O) (Sigma-Aldrich) was added. After the color of the solution changed from dark blue to bright red, the solution was left to boil for another 5 min while being stirred. Finally, the GNP solution was brought to room temperature while being stirred.
The GNPs were characterized by Transmission Electron Microscopy (TEM) (H7000; Hitachi Corp., Tokyo, Japan), UV-spectroscopy (Lambda 40; PerkinElmer, Waltham, MA, USA), Hyper Spectral Imaging (HSI), and by Dynamic Light Scattering (DLS) using a 90 Plus Particle Sizer Analyzer (Brookhaven Instruments Corp., New York, NY, USA) to determine the size of the NPs.

The GNPs were synthesized via the reduction of HAuCl₄ by sodium citrate, which is more commonly referred to as the Turkevitch’s method [29 ]. By varying the amount of sodium citrate, this method can yield NPs of varying sizes. In summary, 300 µL of 1 % gold salt was added to 30 mL of doubled distilled water and brought to boil while stirring. The amount of reducing agent (1 % sodium citrate) added was 400 and 100 µL to produce 20 and 50 nm, respectively. The GNPs were characterized by transmission electron microscopy (TEM, H7000, Hitachi Corp. Tokyo, Japan), UV-spectroscopy (Lambda 40; PerkinElmer, Waltham, MA), and dynamic light scattering (DLS) using 90 Plus Particle Sizer Analyzer (Brookhaven Instruments Corp. New York, NY) to determine the size of the particles. The UV–visible peak wavelengths for 20 and 50 nm GNPs were 520 and 525 nm, respectively. According to TEM, the diameters of the NPs were 19.5 (±3.3) and 52.4 (±5.2). According to DLS measurements, the hydrodynamic diameters of the NPs were 24.2 (±0.6) and (52.6 ± 0.8). This information is given under supplementary information as well.