Question

What can be done to get “smear” to dry more quickly before heat fixing. Also, please identify two things that you should decidedly not do to get to speeey up the air drying

Answer 1

The Following are the Methods/steps that can be followed to get “smear” to dry more quickly before heat fixing:

• One simple method is to completely air-dry the slide for 5-10 mins, without applying heat,Because If we heat the slide before it is completely dry, then you end up “boiling apart” the cells. The vapor pressure inside the cells will burst them.
• We can also use a Slide drier which helps to completely air-dry the smear before heat fixing it.
• The smaller the drop, the faster it dries.So always make sure that tthe smear is made using a smaller drop of innoculum for it to dry faster.
• Take the right amount of innoculum for making a smear.Always note that If it is clear, there are too few bacteria, if it looks milky, there are too many bacteria.
• Use the right apparatus for making a smear like an inoculating needle is used to make a smear from an agar colony and an inoculating loop is used to make a smear from a broth culture.
• The smear may be alternatively fixed by using methanol as well, by adding 1-2 drops of methanol onto the dried smear, draining off the excess methanol, and allowing it to air dry. This method minimises damage to host cells, giving a cleaner background.

The two things that should NOT be done to speed up the air drying process are:

1. Do Not wave the slide around.
2. Do Not blow on it as this will disperse bacteria into the air.
3. Note that while the smear is wet, the cells are alive and should be treated as a biohazard.