User:Helen L. Slucher/Notebook/CHEM-572/2014/02/05

From OpenWetWare
Jump to navigationJump to search
Project name Main project page
Previous entry      Next entry


  • To synthesize citrate-coated GNPs 40-45nm in size
  • To synthesize polydopamine-coated GNPs

Citrate Coated GNPs

  1. Prepare stock solutions
    1. Dissolve HAuCl4 in water to have a solution of 10mM
    2. Dissolve 250mg of the citrate sodium salt into 25mL of water
  2. In a beaker mix 50mL of water and a volume of the gold stock solution corresponding to 1.214*10^-2 moles of Gold
  3. Bring solution to a boil
  4. Add a 0.5mL of the citrate sodium solution and reflux for 30 minutes
    1. Note color change from dark blue to red

Polydopamine Coated GNPs

  1. Dissolve dopamine in 100mL Tris Buffer to have a 10mM solution at pH=8.5
  2. Mix 17mL of AuNP solution with 17mL of the dopamine solution
  3. Stir under air at room temperature for 1 hour
  4. Purify by centrifuging and then redisperse in water.
  5. Filtrate through syringe filters with cellulose acetate membranes with pore size of 1um
  6. Make 2 solutions.
    1. to be stored over night on lab bench
    2. to be stored over night in the refrigerator


  • GNP solution turned blue then red after adding citrate
  • We made a second and third citrate GNP solution
  1. Solution 1: 17 nm
  2. Solution 2: 20-25 nm
  3. Solution 3: 15 nm
  • We made a buffer of pH 5 using acetic acid and potassium acetate
  • The GNP solution began turning purple after the addition of polydopamine