User:Dhea Patel/Notebook/Experimental Biological Chemistry Notebook/2012/09/05

AU Biomaterials Design Lab

Objectives

to re-make the Au/BSA solutions, because the mixtures from yesterday did not react,
to re-suspend the fibers in varying concentrations of Tris Buffer with pHs 10 and 8, and
to run UV-vis on the resuspended fibers.

Re-making Au/BSA solutions
- After the Au/BSA solutions were remade, UV-Vis was run on the samples to measure their absorbance.

Adjustments:

The spatula was wrapped in parafilm to measure out both the BSA and the HAuCl₄.
Only one concentration was made initially as a test. It was placed in the oven at 85°C for an hour to make sure a reaction was taking place. This TEST sample was removed after an hour. Dark Blue/Purple fibers formed. This TEST sample was saved for later testing.
After it was confirmed that a reaction was indeed taking place, the mixtures were made with concentrations of 60μM, 80μM, 100μM, 120μM, 128μM, 130μM, 132μM, 133μM, 134μM, 136μM, 138μM, 140μM, 160μM, and 170μM, taking into account the new masses and new actual concentrations of the stock solutions.

Re-suspending Fibers
- Please refer to Melissa's entry for details on centrifuging the Au/BSA solutions and adding the Tris buffer.
  - 2 different pHs of Tris buffer were tested: pH 8 and 10.
  - The concentrations of each pH of Tris buffer was observed using 1 mM, 100 μM, and 10 μM Tris buffer on fibers with arbitrary AU/BSA molar ratios.

UV-vis
- UV-Vis was run on 1mL of the resuspended fibers, with the wavelength range of 700-200nm, looking for a peak around 550nm.
- The data was plotted on an Absorbance vs. Wavelength graph.

Stock Solution Concentrations	'	'	'	'
Theoretical			Actual [uM]
BSA	HAuCl4		BSA	HAuCl4
15 uM	10 mM		15.355	10501

UV-Vis of Resuspended Fibers via Tris Buffer
- Please refer to Melissa's Entry on UV-Vis Analysis to see the graph of Absorbance of AuNP/BSA fibers at various concentrations, resuspended in tris buffer at pH 8 and 10.
- This graph shows the varying absorbances at 545nm, base on the buffer's acidity and concentration.

The stocks were made with the incorrect concentrations, so the reaction did not occur properly.

All the solutions from the batch made on September 5th and a close-up of the solutions from the batch made on September 5th. The solution was made with the parafilmed spatula. THe solution spent 4 hours in a 85°C oven.