The Effect of Temperature on the Aggregation of Colloidal Gold

Shannon Cattie

Problem

How does temperature affect the rate of aggregation of colloidal gold?

Background Information What is Colloidal Gold?

Binary liquid mixture, containing gold nanoparticles Can be ingested orally to treat arthritis, hypertension, skin

conditions, heart rhythm, depression, inflammation, circulation, pain and stress relief, nerve complaints, and act as an IQ booster

History of Colloidal Gold Appearance in the Old Testament of the Bible (Exodus 32) ▪ Moses makes a make-shift colloidal gold to cure the impatience and

disobedience of the nation of Israel Alexandria, Egypt▪ Alchemists discussed the Elixir of Life▪ 16th century: alchemist, Paracelsus, founded the school of iatrochemistry,

the chemistry of medicines - beginning of modern pharmacology Ancient Rome▪ Used to stain glass a deep red

Used for photography in 1842 in the process of crysotype

Background Information Nanotechnology

Deals with processes that take place on the nanometer scale, which is one billionth of a meter.

Properties of metals are different on the Nano scale than in bulk.▪ Gold in bulk is a yellowish color, but gold’s nanoparticles are

a wine-red Aggregation

The formation of aggregates causing a change in color For the most part, irreversible An aggregate is a group of particles which are held

together; they can be held together in any way

Background Information Why add Salt to Aggregate Colloidal Gold?

Gold particles in colloidal solutions are negatively charged, so they repel each other. They cannot clump together.

Salt shields negative charges, causing clumping

Why does Colloidal Gold turn Blue after Aggregation? Because of the change in the light spectra

Salt (NaCl) Suppose to lower the temperature in which aggregation

occurs Enhances aggregation

Hypothesis

If the temperature of colloidal gold is raised, then the particles of the colloidal gold will aggregate more readily than those at lower temperatures.

Materials

Journal Pen Aluminum foil Refrigerator Thermometer A micro pipette Spectro Vis Logger Pro 10mL graduated cylinder Paper towels

MaterialsTO MAKE THE COLLOIDAL GOLD 20 mL of 1mM

hydrogen tetrachloroaurate solution

Distilled water 2mL of 1% trisodium

citrate solution A hot plate An Erlenmeyer flask Graduated cylinder Crucible tongs

FOR EACH TRIAL

A cuvette and cap 1000 μL of 1 M

sodium chloride solution

3mL of colloidal gold 100μL of the solution

Procedure – Making the Colloidal GoldMake the Colloidal Gold1. Measure 20 mL of 1mM hydrogen tetrachloroaurate solution in a graduated

cylinder2. Pour the 20 mL of 1mM hydrogen tetrachloroaurate solution into a 250 mL

Erlenmeyer Flask3. Add distilled water to the 200 mL mark on the Erlenmeyer flask4. Place the Erlenmeyer flask onto a hot plate and turn the hot plate on a

medium-high setting5. Bring to a gentle boiling6. Measure 2mL of 1% trisodium citrate solution using a 10 mL graduated

cylinder 7. Add the 2mL of 1% trisodium citrate solution to the boiling solution in the

Erlenmeyer flask8. Continue heating the solution at a gentle boil for about 10 minutes until the

solution is stable at a ruby or wine-red color and no longer changes color9. After the color stabilizes, remove the Erlenmeyer flask from the hot plate

and allow to cool10. Add distilled water until the solution reaches 200 mL again

Procedure – Testing the Aggregation1. Begin by hooking up the spectrometer to the computer and opening

Logger Pro

2. Measure 3 mL of Colloidal gold into a 10 mL graduated cylinder

3. Pour it into a cuvette

4. Cap the cuvette, wipe the sides of excess liquid, and place into the spectrometer

5. Locate the peak of absorption on the graph and record

6. Heat colloidal gold to 30°C by using a hot plate, let sit for the day and accumulate to room temperature (10°C), or place in refrigerator and cool to 10°C

Procedure – Testing the Aggregation7. Collect the location of the peak of absorption on each graph after following this procedure:

a. Add the colloidal gold to the cuvette

b. Measure 100 microliters of sodium chloride solution using a micropipette

c. Add the 100 microliters of sodium chloride solution into the cuvette

d. Shake the cuvette once, and let sit for approximately 20 seconds

e. Place into Spectro Vis

f. Collect data

g. Repeat ten times

Variables

Independent variable: Sodium chloride solution

Dependent variable: Aggregation ratE

Control: Room temperature

Constants: Colloidal gold and amount of sodium chloride solution added

Data – Colloidal Gold at 10°C

0 100 200 300 400 500 600 700 800 900 10000

100

200

300

400

500

600

700R² = 0.856479451489213

Colloidal Gold at 10°C

Sodium Chloride Solution (μL)

Peak

of

Gra

ph (

nm)

0 100 200 300 400 500 600 700 800 900 10000

100

200

300

400

500

600

700

Colloidal Gold at 10°C

Sodium Chloride Solution (μL)

Peak

of

Gra

ph (

nm)

Data – Colloidal Gold at 20°C

0 100 200 300 400 500 600 700 80 900 10000

100

200

300

400

500

600

700R² = 0.784995317000275

Colloidal Gold at 20°C

Sodium Chloride Solution (μL)

Peak

of

Gra

ph (

nm)

0 100 200 300 400 500 600 700 80 900 10000

100

200

300

400

500

600

700

Colloidal Gold at 20°C

Sodium Chloride Solution (μL)

Peak

of

Gra

ph (

nm)

Data – Colloidal Gold at 30°C

0 100 200 300 400 500 600 700 800 900 10000

100

200

300

400

500

600

700R² = 0.87730818750286

Colloidal Gold at 30°C

Sodium Chloried Solution (μL)

Peak

of

Gra

ph (

nm)

0 100 200 300 400 500 600 700 800 900 10000

100

200

300

400

500

600

700

Colloidal Gold at 30°C

Sodium Chloried Solution (μL)

Peak

of

Gra

ph (

nm)

Data – Comparison of all Three

0 100 200 300 400 500 600 700 800 900 1000400

450

500

550

600

650

700

Rate of Aggregation Between Three Temperatures

10C20C30C

Sodium Chloride Solution (μL)

Peak

of G

raph

(nm

)

Data – Comparison of all Three

0 100 200 300 400 500 600 700 800 900 1000400

450

500

550

600

650

700

R² = 0.856479451489213R² = 0.784995317000275R² = 0.87730818750286

Rate of Aggregation Between Three Temperatures

10C Linear (10C)

20C Linear (20C)

30C Linear (30C)

Sodium Chloride Solution (μL)

Peak

of G

raph

(nm

)

Conclusion The data received showed all three temperatures

aggregated similarly. The hypothesis was rejected at the temperatures tested. Further testing would be needed to conclude whether

higher temperatures of colloidal gold increase the rate of aggregation.

Importance of this experiment: Pertains much to recent scientific discoveries about

nanotechnology Nanotechnologists are testing the ability of colloidal gold

to target cancer tumors.

Possible Errors and ImprovementsPossible Errors: The testing taking place on different days

o Slight temperature, humidity, and weather change Change in temperature as the trials were being done

o Temperature was not monitored after being placed in the cuvetteo Solution could have accumulated to room-temperature without

acknowledgement, although efforts were made to work quickly in order to manage this temperature change.

Sodium chloride solution not beginning at the same temperature as the colloidal gold

Improvements to this experiment: Make the sodium chloride solution the same temperature as the

colloidal gold, removing any difference in temperature between what was recorded

Monitor the solution temperature during procedure

Works Cited Aslan, K., Lakowicz, J. R., & Geddes, C. D. (2004, Winter/Spring). Nanogold-plasmon-resonance-based glucose sensing. Retrieved from http://www.theinstituteoffluorescence.com/Publications%20PDF/23.pdf Colloidal Gold [Medical treatments using colloidal gold]. (1971). Retrieved from http://www.alchemistsworkshop.com/ CytImmune Sciences. (2011). What is Colloidal Gold? Retrieved from http://www.cytimmune.com/ go.cfm?do=Page.View&pid=15 Goldman, M. V. (n.d.). Absorption Spectra. In Absorption Spectra. Retrieved from Colorado Commission on Higher Education and the National Science Foundation website: http://www.colorado.edu/ physics/2000/quantumzone/fraunhofer.html IUPAC. (2002, September 5). STABILITY OF COLLOIDAL SYSTEMS, AGGREGATION, COAGULATION, FLOCCULATION. Retrieved from http://old.iupac.org/reports/2001/colloid_2001/manual_of_s_and_t/node35.html Malvern Instruments Ltd. (2011). Colloidal Aggregation. Retrieved from http://www.malverninstruments.fr/LabEng/industry/nanotechnology/colloids_aggregation.htm NANOYOU. (2011, July/August). Experiment with colorimetric gold nanosensors - Teacher guide (age 11-13) [A Teacher's guide for experiments with colloidal gold]. Retrieved from http://www.slideshare.net/NANOYOUproject/ experiment-with-colorimetric-gold-nanosensors-teacher-guide-age-1113 Otwinowski, J. (2007, August 26). Temperature Induced Aggregation of Colloids [Journal testing the effects of temperature on aggregation of colloids]. Retrieved from http://staff.science.uva.nl/ ~pschall/People/Alumni/Thesis_JakubOtwinowski.pdf Science In Motion. (2010). #24 Study of Colloidal Gold Solution. Retrieved from http://www.philasim.org/newmanual/exp24.pdf Solomatin, S. V., Bronich, T. K., Eisenberg, A., Kabanov, V. A., & Kabanov, A. (2004, February 17). Colloidal Stability of Aqueous Dispersions of Block Ionomer Complexes:  Effects of Temperature and Salt [The effects temperature has on colloidal gold]. Retrieved from http://pubs.acs.org database. Space Today Online. (2003). Understanding Space Technology Spectrometers . Retrieved from http://www.spacetoday.org/SolSys/Spectrometers/Spectrometers.html The Physics Classroom. (1996-2012). Color and Vision. Retrieved from comPADRE website: http://www.physicsclassroom.com/class/light/u12l2a.cfm Utopia Silver Supplements. (2005). The First Spiritual Recipe by The Great Physician [The history of Colloidal Gold]. Retrieved from http://www.colloidalgold.com/history.htm