Welcome to Nanolab Nineteen, the game where you find out if you have what it takes to survive in the Nanolab. First, choose you fighter. Will you pick Shelby, the polymer film guru? Or will you choose Claire, the nanorod master? Or maybe you will select Vivian, the only one brave enough to tackle organic synthesis? Choose carefully, and good luck!
Choose your player, Shelby, a senior Chemistry major from West Virginia! This is her second summer in the Nano Lab so she’s got a few syntheses under her belt, but she’s not all work with no play. She loves all things superheroes, binge-watching TV shows, and enjoying a cider and burger at ABC! Pick Shelby to journey to the world of Trial-and-Error! Along the way you can learn about oxyphilic metal trends, nanoparticle synthesis and protocols, polymer trends, and film stability. Collect 5 coins for your golden star (one correct answer = 1 coin)! Scroll down for more!
Choose your player, Claire, is also returning for her second summer in the Nanolab. While she doesn’t have as much experience as Shelby, she is ready and raring to take on some nanorods. Claire is a senior Chemistry and Anthropology double major from Massachusetts. When she is not in the lab, Claire loves going on long walks and reading books. Armed with a pH probe and some sodium hydroxide, she will guide you through the world of Try-It-Again. Learn about gold nanorods, rod assembly, and conformational changes. If you get all 5 coins, you may achieve helical rod assembly! If not, you can always Try It Again!
Choose your player, Vivian, a sophomore Chemistry major, economics minor, and has Pre-Health professions concentration from New Oxford, PA. This is her first summer in the Nano Lab, very fresh and new. She loves riding motorcycles, getting tattoos, hanging out with her friends, and being outdoors. Pick Vivian to escape to the world of Learning-As-You-Go. Come learn about extractions, rotovapping, columns, NMR, and TLC (Don’t worry I’ll be learning along with you)! Collect 5 coins for your golden star (one correct answer = 1 coin)! Scroll down for more.
1.) Which metal is more oxyphilic?
Answer: 3: Copper is the most oxyphilic metal here, followed by silver, then gold! We are using this oxyphilic trend to predict ratios of polymers to nanoparticles needed for stable nanoparticle films based on our metallic nanoparticle/polymer compatibility.
2.) What is the most common way to synthesize aqueous citrate capped gold nanoparticles?
- Turkevich Method
- Thompson Method
- Faraday Method
Answer: 1: The Turkevich Method is the most common method used by scientists for making citrated capped AuNPs around 15-20 nm in size in aqueous solution (but Faraday did create AuNPs over 150 years ago – click the link to learn more!) https://www.rigb.org/our-history/iconic-objects/iconic-objects-list/faraday-gold-colloids
3.) What is sodium citrate’s role in nanoparticle syntheses?
- Capping agent
- Reducing agent
- Both A and B
Answer: 3: Depending on the synthesis, sodium citrate can act as either a reducing agent or capping agent, or sometimes both! Reducing agents are used to create metal atoms in order to grow particles, and capping agents are needed to control particle size and avoid aggregation.
4.) What is the appropriate way to collect and clean your nanoparticles?
- Cell Filtration
- Both A and B
Answer: 3: We can use both centrifugation and cell filtration in order to clean away excess capping and reducing agents and collect concentrated stocks of our nanoparticles! It can be a finicky process, depending on the size and type of particle you’re working with.
5.) Which polymer has the lowest glass transition temperature?
- Poly(methyl methacrylate)
- Poly(vinyl acetate)
- Poly(isobutyl methacrylate)
Answer: 2: Poly(vinyl acetate) is the polymer listed here with the lowest glass transition temperature of 30 ºC. The glass transition temperature (Tg) essentially tells us the rigidity of our polymer (it’s the temperature you heat the polymer to where it changes from a glassy and brittle state to something more flexible). Poly(methyl methacrylate) and poly(vinyl acetate) have Tg’s of 114 ºC and 47 ºC, respectively. The Tg is a polymer property that the Nano Lab is using to explain and predict nanoparticle-polymer film stability.
Congratulations! You have traveled through the world of Trial-and-Error! Hopefully, you’ve earned 5 coins to receive your golden star! If not, don’t worry; that is what this world is all about. Try again!
- Which of the following chemicals can affect gold nanorod length?
- Cetyltrimethylammonium bromide
- Silver nitrate
- Dihydrogen monoxide
Answer: 2! During the synthesis process, the amount of silver nitrate added will affect the aspect ratio of the nanorods. Cetyltrimethylammonium bromide (CTAB), on the other hand, acts as the capping agent on the nanorods and gives the rods a positive charge.
- What color are gold nanoparticles?
- Any color
Answer: 4! The color of the nanoparticles depends on the size. In the lab, nanospheres tend to be red, while the nanorods can range from blue-green to brown. In water, oxidized gold (Au3+) is the typical yellow-gold color.
- In layer-by-layer deposition, nanoparticles can be coated with oppositely charged polymers. Which of the following has a positive charge and acts as the final coat?
- Polyanethol sulfonate
- Polyacrylic acid
Answer: 1! Poly-L-Lysine has a positive charge, and can form different shapes (conformations) based on the conditions. In normal conditions, PLL is in a random coil, but as you increase the pH it will shift to alpha-helix and an increase in temperature will result in beta-sheet conformation. Polyanethol sulfonate and polyacrylic acid, on the other hand, are both negatively charged and act as “middle layers.”
- Which of the following instruments is primarily used to detect rod assembly:
- Circular dichroism spectrophotometer
- UV-Vis Spectrometer
Answer: 3! UV-Vis can show which wavelengths of light are most absorbed by the nanorods. When nanorods clump together, the absorption changes dramatically. The zetasizer can also be used to approximate the size of the nanorod assemblies. The circular dichroism, though, is used to detect which conformation the PLL is in.
- You got some interesting UV-Vis results on the last pH test you ran. What do you do now?
- Try to repeat the results
- Consider your job done, and resign
- Sprain your ankle to get out of work early
Answer: 1! While we can neither confirm nor deny Answer 3, interesting results don’t mean anything unless they can be repeated. So get back to work, and get that data!
If you collected all 5 coins, congratulations! You get a gold star. Did you achieve helical assembly? Nanorods can be difficult sometimes, and it is unclear with your current set of data. Whatever your results are, feel free to go back and Try It Again!
- What molecule is this?
Answer: 3: This molecule is bromoundecylacrylate. The difference between these three choices is what is on the right end of the molecule. As shown above, bromoundecylacrylate has only a single hydrogen bound to the one end. If this was bromoundecylmethacrylate, the hydrogen would be replaced with a methyl group. If this was 11-bromoundecanol, there would only be a hydroxyl group after the carbon chain.
- When doing an extraction, which layer do you take out using the separatory funnel?
- Organic layer
- Aqueous layer
- Intermediate layer
Answer: 2: You take out the aqueous layer, because your synthetic material is less dense above the aqueous layer, which is the object you want to keep so that you can continue with your synthesis.
- When rotovapping, what liquid are you putting your dry ice into in the condenser?
Answer: 1: The correct answer is 2-propanol gets colder faster since it has a higher freezing point.
- What do peak integrations stand for in H NMR?
- Number of protons at that specific part of the molecule
- The concentration of your sample
- Polarity of your molecule
Answer: 1: The peak integration indicates the number of protons at a specific part of your molecule based off your first integration of a known peak of your molecule.
- Why are columns used in organic chemistry?
- To combine materials
- For purification
- For titrations
Answer: 2: Columns are done to separate a product from its impurities through a filtration technique, in which fractions are taken from the column with the idea that the product will come through the column faster than its unreacted materials and impurities.
Great Job! You have wandered through the world of Learning-As-You-Go! If some topics are still fuzzy to you, just keep on moving forward because you’ll learn more as you go!
Did you collect all three stars? If you did, congratulations!
You have the skills to survive the Nanolab! Now it is time to meet the Game Master, Dr. Thompson…
An avid coffee drinker, Dr. Thompson will decide your fate in the Nanolab. He holds the answers to all questions, but he can be elusive at times. Solve his quests, and you can level up in the Nanolab!