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

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Objective To synthesize citrate-coated GNPs 40-45nm in size To synthesize polydopamine-coated GNPs Citrate Coated GNPs Prepare stock solutions Dissolve HAuCl4 in water to have a solution of 10mM Dissolve 250mg of the citrate sodium salt into 25mL of water In a beaker mix 50mL of water and a volume of the gold stock solution corresponding to 1.214*10^-2 moles of Gold Bring solution to a boil Add a 0.5mL of the citrate sodium solution and reflux for 30 minutes Note color change from dark blue to red Polydopamine Coated GNPs Dissolve dopamine in 100mL Tris Buffer to have a 10mM solution at pH=8.5 Mix 17mL of AuNP solution with 17mL of the dopamine solution Stir under air at room temperature for 1 hour Purify by centrifuging and then redisperse in water. Filtrate through syringe filters with cellulose acetate membranes with pore size of 1um Make 2 solutions. to be stored over night on lab bench to be stored over night in the refrigerator Data GNP solution turned blue then red after adding citrate We made a second and third citrate GNP solution Solution 1: 17 nm Solution 2: 20-25 nm 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