"microphone" qualifies "amplifier", meaning that it's an amplifier designed for processing signal coming from a microphone.

The title is a word play summarizing the fact that the author used such an amp to record biological signals. In context, it doesn't means or even imply that he uses a microphone.

Edit: word play, not pun; Edit2: +s; 3: better still.

*she

*I wish English had a proper personal, gender-neutral pronoun.

Editing, anyway.

They. Yes, if you're not familiar with it, it looks like the plural form, but it has been used to denote individuals even before "political correctness" became a thing.

Thon could also use https://en.wiktionary.org/wiki/thon

edit: that part meant jokingly (please). Although https://en.wikipedia.org/wiki/Old_English_grammar#Pronouns is far more interesting.

The proper personal, gender-neutral pronoun in English is "they"

Yeah but "that they" is awkward.

I took it as a wordplay on "microphone amplifier" and "bioamplifier"