Materials and methods
This section must be clear and detailed enough for another person in your field to repeat the experiments and reproduce the results. Previously described protocols may be referenced but you must clearly outline any changes made to the previous approach. Referencing must be very accurate, referring to the original description of a technique. Only provide full details of a technique if your methods are new (unpublished).
“The FISH method was modified from that previously described by Callen et al (1990) in that chromosomes were stained prior to analysis with both propidium iodide and DAPI.”
The materials and Methods section should be written in the past tense, and usually in the passive voice.
“Melanoma cells were washed twice with medium and fresh medium containing sense or antisense oligomers (5 µm) was added.“
Do not use the imperative form, that you may use for laboratory notes.
“Wash cells twice with medium and then add antisense oligomers (5 µM).”