Autoclave
What are they and why do we use them? What types are there?
An autoclave uses high pressure and temperature to sterilise lab equipment and media. It is a critical piece of infrastructure for any lab because freshly sterilised inputs are required every day.
Autoclaves tend to differ based upon size, load-method and cycle type.
Size
Small <25 L - Perfect for a small lab of 2-3 people.
Medium 25-100 L - Can be shared between 20-30 researchers across multiple labs, with a bit of waiting.
Large >100 L - Generally at this scale you’d have a dedicated autoclave engineer who runs the steam sterilising for an entire building.
Load-method
Top-Load - Lift the lid and drop items into the barrel of the autoclave within baskets.
Front-Load - Open the lid and slide out the trays. Seen in image above.
Cycle Types - Most autoclaves should be capable of at least 1 of these standardised cycles. The cycle is the duration of temperatures and pressures that items placed in the autoclave will be subjected to. The most useful cycle for a biotech lab is the liquid cycle;
Liquid Cycle - 121˚C/15 psi
Solid Cycle - Don’t care
Agar Cycle - Doesn’t matter
Unless you’re dealing with a particular tricky microorganism, focus on obtaining an autoclave with a good liquid cycle that can reach 121˚C/15 psi. Use it for everything, including solids and agar.
When do you use?
For sterilising any equipment or media that you need for experiments in synthetic biology.
For sterilising NON-FLAMMABLE buffers.
How do you use?
Never autoclave tightened vessels. Loosen all lids by half a turn or you will have an explosion.
Place items in the autoclave, check all important water levels, close the lid, run the cycle, come back ~1-2 hours later and retrieve your sterile goods.
You should absolutely hunt down a machine specific manual and read the instructions thoroughly before operating any autoclave. I can however give you some general tips;
Most autoclaves require some water in the bottom of the sterilisation chamber. Running an autoclave of this type dry can have disastrous results… Fill up the chamber so that the heating element is completely submerged in water.
There will also be a seperate water reservoir that provides additional water to the chamber. Make sure that the water level in this is correct.
There may be a waste water container out the back that collects overflow. Make sure this doesn’t fill up in order to avoid a mess - this is the least important one as neglect won’t break anything… just make a mess.
Autoclave tape or Sterilization Indicator Strips can be added to ensure the chamber is reaching the correct temperature and pressure for sterilisation.