User:Keyun Wang/Notebook/Experimental Biological Chemistry I/2012/09/04

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  • To run UV-Vis analysis on Au/BSA solutions at various ratios.
  • To remake solutions that did not give expected results.
  • To make Tris Buffer at 100mM at pH 8.0 and 10.0


  • The absorbance of each sample were taken by UV-vis spectrophotometer. Data with absorbance versus wavelength were obtained. The original sets of Au/BSA solution failed to work, and thus new sets of solution made by Dr. Abigail Miller were used for UV-vis spectrum. See Dhea Patel's Lab Notebook on 2012/09/04 for details regarding the appearance of unsuccessful solutions made last week and reacted solutions made by Dr. Abigail Miller.
  • Solutions of Au/BSA at various ratios were remade at newly calculated amounts. See Dhea Patel's Lab Notebook on 2012/09/04 for the details on each amount and concentration of HAuCl4 and BSA stock solution was used for each Au/BSA ratio. New stock solutions were remade. Solutions were wrapped around with aluminum foil and placed in incubator at 85°C for five hours. Incubator were cooled to room temperature until the next day.
  • Theoretical amount of 0.1M Tris buffer with original formula weight of 121.14g/mol were roughly calculated by weighted out with 12.114g of tris mixed with 100mL of water. For details of the calculation, please refer to Melissa's Notebook for the calculation of 0.1M tris buffer solution. Two sets of solutions were made. In each 100mL tris buffer, each sample was titrated to pH 8.0 and pH 10.0 with the addition of 1M HCl, respectively.
  • New sets of Au/BSA solutions at various ratios that were pre-made on 2012/09/04 before were placed in centrifuge and were attempted to spin at 4000rpm for 5 minutes in room temperature. However, two glass test tubes that were placed on the outskirts of centrifuge shattered during the process. Glass tubes broke during the process of centrifugation and were put to halt as a result. All solutions were then transferred into falcon tubes. The Au/BSA solution at ratio 130 and 128 were disposed due to mix of broken glass. Some purple fibers were stuck on glass test tubes while being transferred to falcon tube and are lost during the transfer.


  • The original sets of solutions did not form nano-particles, solutions appeared yellow in color. It was predicted that the HAuCl4 reacted with gold specula during the transfer.
  • A new set of solutions with different Au/BSA ratios were made beforehand at the exact same ratio and concentrations. It was hypothesized that the spectula used during BSA weighting interacted with the BSA and thus undergo structural confirmation. This allowed the BSA stock to be inefficient to interact with the HAuCl4. As a result, the concentration of solutions for Au/BSA ratios were not changed. For details of the concentrations, see Notebook from 2012/08/29
  • The new set of solutions with different ratios of Au and BSA made in 2012/08/29 appeared purple in color. The 60 Au/BSA solution appeared cloudy and white. The 80 Au/BSA solution appeared as a purpose homogenous solution. The Au/BSA solution with other ratios are transparent with purple fiber formations.