Matt Hyde

Essentials of Biotechnology

Unit 1: intro. To Biotech

What is a Microcentrifuge?

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• A laboratory machine that spins small tubes at high speeds.
• The spinning motion creates a force (centrifugal force) that separates substances based on their density.
• It's an essential tool in fields like molecular biology, biochemistry, and genetics.

Key Vocabulary:

• Centrifuge: The machine itself.
• Rotor: The spinning part of the centrifuge where the tubes are placed.
• Microcentrifuge Tube: A small plastic tube used to hold the sample.
• Supernatant: The liquid portion of a sample that remains at the top after centrifugation.
• Pellet: The solid portion of a sample that settles at the bottom of the tube after centrifugation.

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Step 1: Balancing the Rotor

• This is the most critical step!
• Always load tubes in pairs, directly opposite each other on the rotor.
• The tubes must have equal volume to ensure the rotor is perfectly balanced. If a tube is unpaired, fill a tube with an equal volume of water and place it opposite the sample to balance the load.
• An unbalanced rotor can vibrate violently and cause damage to the machine, the samples, and potentially cause injury.

Step 2: Securing and Setting

• Close the lid of the rotor and the lid of the centrifuge securely.
• Set the desired speed (in RPM or RCF) and the duration of the spin.
• Remember to always start with the lid closed.

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After the Spin:

• Wait for the rotor to come to a complete stop before opening the lid.
• Carefully remove the tubes, being cautious not to disturb the pellet at the bottom.

Analyzing Your Sample:

• You now have a separated sample!
• The pellet is the dense material at the bottom.
• The supernatant is the liquid on top.
• You can now choose to save the supernatant, the pellet, or both, depending on your experiment.
• Dispose of the tubes and materials properly when finished.

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Your Turn! Now it's time to put what you've learned into practice. Head to the centrifuge stations with your lab partner.At the common workstation, you'll find a variety of sample tubes. Each tube contains a different mixture that's waiting to be spun up.

1. Go To your Station. You may have two or three centrifuge tubes at your station.
2. Select a sample: each group member will go to the common supply station in the room to fill your centrifuge tubes with any of the available samples.
1. Remember that you need to be consistent.
2. Agree to add either 0.5, 1.0, or 1.5 mil of sample to each tube.
3. Only one group member can leave the lab station at a time.
3. Make a prediction: Look at the tube and discuss with your group what you expect to happen. Will it separate into layers? What will the top and bottom layers look like?
4. Prepare your centrifuge: Follow the safety instructions carefully.
5. Spin the sample: Place your tubes in the centrifuge and run it for the designated time and speed.
6. Observe your results: What happened? Were your predictions correct?

Safety First! Centrifuges are powerful machines. It is critical that you follow these instructions to ensure everyone's safety.

1. Wear your safety goggles. This is required at all times.
2. Balance is everything. When you place your tube in the centrifuge, you must place a second tube of equal weight directly opposite it. If you only have one sample, you must use a "balance tube" filled with the same amount of water.
3. Secure the lid. Always make sure the centrifuge lid is closed and latched properly before you start the machine.
4. No peeking. Do not open the lid while the centrifuge is spinning. Wait for the rotor to come to a complete stop before retrieving your sample.
5. Handle with care. Once the samples are done, handle the tubes carefully to avoid disturbing the separated layers.