User:Elaine Marie Robbins/Notebook/CHEM-496/2012/03/06

Objective

To determine the effect of the mole ratio of Au/BSA on AuNP synthesis.

Description

Effect of Au/BSA Ratio

1. Make solutions with the following Au/BSA mole ratios using 0.1 mL HAuCl₄:
   • 90 Au/BSA
   • 110 Au/BSA
   • 130 Au/BSA
   • 150 Au/BSA
2. Dilute to 1 mL with water.
3. Place in oven at 80°C.
4. Leave solutions in oven for 3.5 hr.
5. Centrifuge solutions for 10 min at 13200 rpm.
6. Take UV-vis data of supernatant.

Effect of Tris Buffer on Protein Fibers

1. Centrifuge AuNP fibers + 50 mM tris solution made on 02/15/12.
2. Take UV-vis absorption data.
3. Compare data to that obtained on 02/15/12, 02/21/12, and 02/28/12.

Data

Effect of Au/BSA Ratio

• 90 Au/BSA Ratio

• 110 Au/BSA Ratio

• 130 Au/BSA Ratio

• 150 Au/BSA Ratio

• Graph of absorbance vs wavelength for each Au/BSA ratio:

The transition from AuNP solution to AuNP/BSA fibers occurs between 130 Au/BSA and 150 Au/BSA.

Effect of Tris Buffer on Protein Fibers

• Graphs of absorbance vs wavelength over time of the AuNP fibers and 50 mM tris (pH 10.1) solution made on 02/15/12:

Notes

Effect of Au/BSA Ratio

After centrifuge, all four solutions had at least some solid present in the solution. Only the 150 Au/BSA solution had a significant amount of visible fiber formation.