User:James C. Schwabacher/Notebook/Protein-Templated Quantum Dots/2015/02/27

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Project Summary

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Original Protocol

  1. Prepare at least 5 mL of 15 mg/mL BSA in deionized water.
  2. Prepare at least 5 mL of 5 mM Mercury (II) nitrate in deionized water.
  3. Pour 5 mL of the BSA solution into a 25 mL round bottom flask; stir this solution in the hood.
  4. Vortex the mercury solution (to help the compound dissolve) and add 5 mL of the solution to the round bottom (while stirring).
  5. Add a few drops of 1 M NaOH to the stirring mixture to achieve ~pH 9. (I most commonly ended up with a pH of 10).
  6. Allow 8-12 hours to pass.
  7. Prepare 5 mL of 20 mM sodium sulfide.
  8. Add 4 mL of 20 mM sodium sulfide to the round bottom (while stirring).
  9. Allow 15 minutes to pass
  10. Transfer to a larger round bottom flask and rotovap the solution with a water bath set to ~40°C.
  11. Once completely dry (a thin film will develop along the sides of the flask), remove from the rotovap.
  12. Slowly add a few mL of DI water while gently swirling the round bottom flask. First, a hydrogel network should form along the sides of the glass as the film rehydrates.
  13. Slowly add more DI water until the hydrogel detaches from the glass and collapses into sol-gel structures suspended in solution.

"Quick" Protocol (15 min Synthesis)

  1. Prepare at least 5 mL of 15 mg/mL BSA in deionized water.
  2. Prepare at least 5 mL of 5 mM Mercury (II) nitrate in deionized water.
  3. Prepare 5 mL of 20 mM sodium sulfide.
  4. Pour 5 mL of the BSA solution into a 25 mL round bottom flask; stir this solution in the hood.
  5. Vortex the mercury solution (to help the compound dissolve) and add 5 mL of the solution to the round bottom (while stirring).
  6. Add a few drops of 1 M NaOH to the stirring mixture to achieve ~pH 9. (I most commonly ended up with a pH of 10).
  7. 'Immediately' add 4 mL of 20 mM sodium sulfide to the round bottom (while stirring).
  8. Allow 15 minutes to pass
  9. Transfer to a larger round bottom flask and rotovap the solution with a water bath set to ~40°C.
  10. Once completely dry (a thin film will develop along the sides of the flask), remove from the rotovap.
  11. Slowly add a few mL of DI water while gently swirling the round bottom flask. First, a hydrogel network should form along the sides of the glass as the film rehydrates.
  12. Slowly add more DI water until the hydrogel detaches from the glass and collapses into sol-gel structures suspended in solution.

Filtration Protocol

I conducted vacuum filtration once using a membrane filter (Supor-450, 47mm, 0.45μm). This worked to separate the gels from the solution, however do not leave the product on the membrane to dry--it will get stuck the membrane.

Summary of Syntheses Attempted

Date Batch Reaction Temp (C) Reaction Time (hrs) Notes Gel Formation?
9/9/2014 JCS 1 23 11.58 no heating Not Attempted
9/16/2014 JCS 2 41 mantle setting 11 Not Attempted
9/23/2014 JCS 3 37 13.5 mantle setting 10 Not Attempted
9/30/2014 JCS 4 23 11.5 no heating Yes (first discovery)
9/30/2014 JCS 5 50 11.5 mantle setting 14.5 Yes
10/7/2014 JCS 6 23 11 no heating Not Attempted
11/4/2014 JCS 7 23 no heating, BSA Control No (Structures did form but were noticeably different)
11/11/2014 JCS 8 23 7.5 Hg into BSA Not Attempted
11/11/2014 JCS 9 23 7.5 BSA into Hg Not Attempted
11/11/2014 JCS 10 Cold Room 7.5 cold room synthesis- no change Not Attempted
11/18/2014 JCS 11 23 48 attempting gel formation again Yes
11/18/2014 JCS 12 23 48 attempting gel formation again Yes
1/22/2015 JCS 13 23 24 No Mercury No
1/29/2015 JCS 14 23 Over Weekend No Sodium Sulfide No (similar to BSA-only)
2/4/2015 JCS 15 23 24 No BSA No (black precipitate)
2/5/2015 JCS 16 23 15 minutes original protocol with changed timeline Yes
2/20/2015 JCS 17 23 15 minutes Decreased BSA conc (x10) No

Determining Sol-Gel formation factors

Sample BSA Mercury NaOH Sulfide Overnight Temp Formed?
JCS13 X X X X Room No
JCS14 X X X X (over weekend) Room No
JCS15 X X X X Room No
JCS16 X X X X Room Yes
JCS17 X (decreased factor of 10) X X X Room No


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