Nanoparticle Synthesis Laboratory Notebook: Martin Method (Chemical Synthesis)

JUNE 14

Experiment & Observation: Gold Nanoparticle Synthesis using Martin Method Optimization Trial #1

A) Perform Martin Method Synthesis Protocol:

Perform all steps in BIOSAFETY CABINET

1. Measure 20 mL of ddH2O into 50 mL graduated cylinder and pour into 125mL Erlenmeyer flask

2. Place the falcon tube containing the remaining ddH2O on ice to keep it cold

3. Weigh out 1.96mg (0.00196g) of chloroauric acid trihydrate (HAuCl4) solid and transfer to a 1.5mL microfuge tube. Seal the tube rapidly to limit air exposure.

-CAUTION: oxidizes quickly - do not expose to air for longer than required.

-Do NOT use metal scoopula - use plastic or wood to transfer the solid.

-LIGHT SENSITIVE - use for short duration under light conditions

4. Quickly add the chloroauric acid to the ddH2O in the flask*

5. Add stir bar to flask and mix on plate to allow the solid to dissolve

6. Weigh out 1.47mg (0.00147g) of trisodium citrate dihydrate solid

7. Add the trisodium citrate dihydrate to the mixture in the flask with stirring

8. On ice, prepare 0.1M sodium borohydride (NaBH4) solution

9. Pipet 0.65 mL (650 uL) of cold ddH2O to a 1.5mL microfuge tube

10. Weigh out 2.46mg (0.00246g) of NaBH4

11. Put the measured NaBH4 into the microfuge tube and resuspend by pipetting until the solid is fully dissolved

12. Keep the solution cold on ice

13. Add 0.6mL (600uL) of cold 0.1M NaBH4 into the solution in the Erlenmeyer flask while stirring vigorously - NOTE: the solution should turn PINK  immediately - indicates particle formation

Modifications:

- 2.01 mg of chloroauric acid was weighed out since it was difficult to measure 1.96 mg of chloroauric acid since it oxidizes quickly.

- It was important to have equal molar ratio of chloroauric acid and its capping agent trisodium citrate. Thus, 1.5 mg of trisodium citrate was weighed out instead of 1.47 mg chloroauric acid.

- The sodium borohydride solution wasn’t as cold as it was supposed to be for high reducing power…

B) Results:

Color formation: Gold nanoparticle solution turned WINE RED instead of PINK. It is important to note that colour can be subjective and can be affected by different conditions.

UV-vis results: An absorption peak was expected at a range of 510nm-524nm more specifically 513±3nm. An absorption peak was found within this range Figure 1.

Figure 1: UV-vis of gold nanoparticles synthesized through Martin method batch #1

JUNE 20

Experiment & Observation: Gold Nanoparticle Synthesis using Martin Method Optimization Trial #2

A) Perform Martin Method Synthesis Protocol:

Perform all steps in BIOSAFETY CABINET

1. Measure 60 mL of ddH2O into 100 mL graduated cylinder and pour into 125mL Erlenmeyer flask

2. Place the falcon tube containing the remaining ddH2O on ice to keep it cold

3. Weigh out 5.88mg (0.00588g) of chloroauric acid trihydrate (HAuCl4) solid and transfer to a 1.5mL microfuge tube. Seal the tube rapidly to limit air exposure

-CAUTION: oxidizes quickly - do not expose to air for longer than required

-Do NOT use metal scoopula - use plastic or wood to transfer the solid

-LIGHT SENSITIVE - use for short duration under light conditions.

4. Quickly add the chloroauric acid to the 60 mL ddH2O in the flask*

5. Add stir bar to flask and mix on plate to allow the solid to dissolve

6. Weigh out 4.41mg (0.00441g) of trisodium citrate dihydrate solid

7. Add the trisodium citrate dihydrate to the mixture in the flask with stirring

8. On ice, prepare 0.1M sodium borohydride (NaBH4) solution

9. Pipet 1.95 mL of cold ddH2O to a 2.0mL microfuge tube

10. Weigh out 7.39mg (0.00738g) of NaBH4

11. Put the measured NaBH4 into the microfuge tube and resuspend by pipetting until the solid is fully dissolved

12. Keep the solution cold on ice

13. Add 1.8mL of cold 0.1M NaBH4 into the solution in the Erlenmeyer flask while stirring vigorously

- NOTE: the solution should turn PINK  immediately - indicates particle formation

B) Results:

Color formation: Gold nanoparticle solution turned a LIGHT RUBY RED instead of PINK. Although this isn’t exactly pink it appears light enough to considered a shade of pink.

UV-vis results: An absorption peak was expected at a range of 510nm-524nm more specifically 513±3nm. An absorption peak was found within this range Figure 2.

Figure 2: UV-vis of gold nanoparticles synthesized through Martin method batch #2

JULY 4

Observation: Gold Nanoparticle Synthesis using Martin Method Optimization Trial #3

A) Results: Surprisingly Batch #1 had a perfect size range with 2-6 nm in size with an average size of 4 nm Figure 3. While batch #2 indicated a size range of about 100 nm! Figure 4. This has clearly indicated that the colour visual wasn’t as conclusive but should be able to tell us that some form of nanoparticles was formed.

Figure 3: Hydrodynamic size determination of gold nanoparticles synthesized through the Martin method batch 1

Figure 4: Hydrodynamic size determination of gold nanoparticles synthesized through the Martin method batch 2

JULY 13

Experiment & Observation: Gold Nanoparticle Synthesis using Martin Method Optimization Trial #4

A) Perform Martin Method Synthesis Protocol:

Perform all steps in BIOSAFETY CABINET

1. Measure 20 mL of ddH2O into 50 mL graduated cylinder and pour into 125mL Erlenmeyer flask

2. Place the falcon tube containing the remaining ddH2O on ice to keep it cold

3. Weigh out 2.01 mg (0.00201g) of chloroauric acid trihydrate (HAuCl4) solid and transfer to a 1.5mL microfuge tube. Seal the tube rapidly to limit air exposure

-CAUTION: oxidizes quickly - do not expose to air for longer than required

-Do NOT use metal scoopula - use plastic or wood to transfer the solid

-LIGHT SENSITIVE - use for short duration under light conditions

-Note: chloroauric acid is pricey - try not to be wasteful!

4. Quickly add the chloroauric acid to the ddH2O in the flask*

5. Add stir bar to flask and mix on plate to allow the solid to dissolve

6. Weigh out 1.5mg (0.00150g) of trisodium citrate dihydrate solid

7. Add the trisodium citrate dihydrate to the mixture in the flask with stirring

8. On ice, prepare 0.1M sodium borohydride (NaBH4) solution

9. Pipet 0.65 mL (650 uL) of cold ddH2O to a 1.5mL microfuge tube

Weigh out 2.46mg (0.00246g) of NaBH4

10. Put the measured NaBH4 into the microfuge tube and resuspend by pipetting until the solid is fully dissolved. Keep the solution cold on ice

11. Add 0.6mL (600uL) of cold 0.1M NaBH4 into the solution in the Erlenmeyer flask while stirring vigorously - NOTE: the solution should turn WINE RED  immediately - indicates particle formation

Modifications:

No modification was done to this newly edited protocol.

B) Results:

Color formation: A gold nanoparticle colloid solution was obtained that was dark wine red colour.

UV-vis results: An absorbance peak was expected at a range of 510nm-524nm (more specifically 513±3nm). An absorption peak was found within this range according to our results. Indicating the successful synthesis of gold nanoparticles.

DLS results: The dynamic light scattering indicated nanoparticles in the 1-10 nm range with most of them being 2-5 nm.

Figure 5: UV-vis of gold nanoparticles synthesized through Martin method batch #3

JULY 21

Observation: Gold Nanoparticle Synthesis using Martin Method Optimization Trial #5

A) Results: of batch#1 and batch#3 samples (since they passed the color formation, UV-vis, and DLS tests)

TEM photos: We have successfully synthesized gold nanoparticles that are 5nm using Martin method according to these images.

Figure 6: TEM of martin synthesized gold nanoparticles batch 1.

Figure 7: TEM of martin synthesized gold nanoparticles batch 3.