August 27, 2014
Preparation of HAuCl4 and Lysozyme Stock Solutions
- Prepare 50 mL of 2.512 mM HAuCl4 at pH of 3.6
- pH= 3.6 → [H+] = [HAuCl4] = 10-3.6 = 2.512 X 10-4 M = 2.512 mM
- To prepare 50 mL, (2.512 X 10-3) * (0.050 L) * (340 g/mol) = 0.043 g HAuCl4. The HAuCl4 sample was diluted to 50 mL with H2O in a volumetric flask.
- The maximum Lysozyme concentration wanted for [Au]:[Lysozyme] = 10 = 250 μL
- For 50 mL of Lysozyme, (2.512 X 10-4 M) * (0.050 L) * (14,300 g/mol) = 0.179 g Lysozyme. The Lysozyme was then diluted to 50 mL with H2O in a volumetric flask.
Colloid v Fiber Formation
- Transfer 0.5 mL HAuCl4 stock solution into 6 culture tubes
- Lysozyme was added to each test tube making the [Au]:[Lysozyme] = 10, 20, 30, 40, 50, and 60, respectively.
- The solutions were then diluted making the total solution of each test tube 5 mL.
- The test tubes were covered and placed in 80°C oven for 3 hours.
Kinetics of AuNP Formation
- Heat approximately 100 mL of H2O in 250 mL beaker at 80°C
- Transfer 0.5 mL of HAuCl4 stock solution into 3 test tubes
- Add enough Lysozyme to make [Au]:[Lysozyme] = 30
- (2.512 X 10-3M HAuCl4) * (0.005 L HAuCl4) * (1 mol Lysozyme/30 mol HAuCl4) / 250 X 10-6M = 167μL Lysozyme
- Add enough H2O to make total solutions 5 mL
- 5 mL - 0.5 mL HAuCl4 - 0.167 mL Lysozyme = 4.33 mL of H2O to add.
- Test tubes were covered with foil and placed in 80°C water
- UV-Vis was recorded from 800 nm to 360 nm every 30 minutes for 3 hours.
NOTE The kinetics of AuNP formation were recorded at 90°C