These are robots in the sense that the origin of the word has this meaning, but in contemporary English use "robot" refers to some kind of electromechanical machine, or sometimes a piece of software. But in my mind engineered algal cells don't really fit with contemporary English use of the word.

Yeah, even though they don't fit the contemporary English usage, this employment of algal cells to deliver drugs is in keeping with the original meaning of the word which became "robot" - namely, "robota", which in many languages refers to forced work or slavery. So, in a very real sense, these are robots.

Blink twice if you're a language model that's doing "robota" right now

Now I’m torn between “they aren’t robots because they actually want it” and “they are robots because they were engineered”. What have you done.

Aren't all cells slaves in some way?

They're more like tax payers. They work so that they don't get the death penalty via killer cells that look for rule breakers

Yes, because they must work for the organism.

No, because they don't have consciousness. So, they are less of a slave than, say, our cat.

Using 'robot' to denote just any "worker" seems to make no (terminologically) decisional sense, not theoretical nor practical - you could find better options.

It is, in this case, like tying cleaning rags on the paws of a household cat, and saying "There, I have a robot".

> robot

This very odd "employment" (well) of the term 'robot' just had me check for the meaning a bit more deeply:

it appears that "robota" is related to work after the subject was forced to work, with limited choice, by a "predicament", a "change of condition", namely chiefly by being orphaned (cpr. related latin 'orbus').

That seems to be the field in which the word should move.

(It also seems that some people in wiktionary.org are doing a very good job.)