User:Daniel Catt/Notebook/Protein Biofilms Exploration/2011/05/31

Protein Biofilms Exploration

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05.31.2011 Purpose The film that was successfully made and manipulated in the previous entry was not robust enough for our purposes, as it was very brittle and, after a short storage time, very easily fell apart. The goal is to craft a stronger material that can be handled over a long enough period of time to allow for secondary study and analysis with other materials. Eventually, we will use the Au/BSA nanoparticles to provide increased strength and longevity to the film. For the time being, however, it is of interest to optimize the strength of the films in their more basic form -- a mixture of zein, ethanol, glycerol, and BSA. Method Part 1 The first bit of the experiment involves increasing the amount of glycerol in the zein solution and to also slightly alter the preparation protocol for that part of the process. Taking the general procedure from the methods portion of a 2004 paper by J.W. Lawton, the solution of zein protein in ethanol was agitated for 30 minutes with a magnetic stir bar and, upon addition of the glycerol, mixed again for an additional 30 minutes.1 Two zein solutions were prepared: one with 30% glycerol on the basis of zein weight, and the other with 40%. Ethanol remained at 90% v/v of solution and zein was 10% w/v of solution. The BSA solution was mixed to 0.015 mM in distilled water and incubated in a water bath that, though eventually held at around 40°C, varied initially from 37-45°C. It remained incubating for 150 minutes. 500μL of the BSA solution was then added to each of the two samples and the total solution was briefly mixed with stir bar and then poured into 9cm petri dishes. These were placed in an incubator at 37°C overnight. Part 2 The second part is to see if there is any significant effect of the BSA solution on the property of the zein film. To do this, another sample was prepared the same as the 30% glycerol sample above, except no BSA was added. Additionally, no water was added, which removed a level of control in the experiment due to the fact that two variables were removed from the experiment. It remains to be seen how the removal of both of these variables will affect the film product. The zein solution was poured onto a 9cm petri dish and incubated overnight at 37°C. References 1Lawton, J.W. Plasticizers for Zein: Their Effect on Tensile Properties and Water Absorption of Zein Films. Cereal Chem. 2004, 81 (1), 1-5. Link to the article