User:Keyun Wang/Notebook/Experimental Biological Chemistry I/2012/09/05

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  • To resuspend gold nano-particle pallets with Tris buffer.
  • To determine the best concentration and pH of Tris buffer for resuspension via measuring the absorbance of resuspended solutions throughout time.
  • To make new sets of Au/BSA solutions with varies ratios.


  • A new sets of solutions of BSA and HAuCl4 mixture were made. New stock solutions of HAuCl4 and BSA were also made.
  • 100mM tris buffer at pH 8.0 and pH 10.0 were diluted with serial dilution to four different concentrations: 10mM, 1mM, 100uM, and 10uM, respectively.
  • Resuspending Au/BSA solutions in Tris buffer
    1. The old sets of solutions of Au/BSA at different ratios were spin in centrifuge at 3000rpm for 5 minutes at room temperature.
    2. The supernatant were poured out. Pallet of different Au/BSA ratios were resuspended in different concentrations and different pH of Tris buffer. The details of buffer-pallet mix is shown in table below:
Ratio of Au/BSA Pallet Tris Buffer Concentrations [mM] Tris Buffer pH
132 10 10
133 1 10
134 0.1 10
136 0.01 10
138 10 8
140 1 8
160 0.1 8
170 0.01 8
    1. The tris buffer and Au/BSA solution were mixed gently and let sit for 30 minutes.
    2. After 30 minutes, 500uL of each sample were loaded into quark cuvette and placed into UV-Vis to measure absorbance from 800nm to 200mm.
    3. Graph were plotted with Absorbance versus Wavelength, for details of absorbance from each sample, see Dhea Patel's Lab Notebook


  • The new sets of solutions made on 2012/09/04 failed to react. The solutions after heating appeared yellow in color. This indicates the BSA failed to react with the HAuCl4 in solution.
  • In this experiment, the tris buffer the fiber were found in previous research to mix back together and create a homologous mixture. However, after the mixing of tris buffer at pH 8.0 and 10.0, no mixture were observed. The procedure from previous experiments cannot be repeated. More concentrations and pH of tris buffer were planned to try out next week for pellet resuspension.