Stable finiteness of monoid algebras and surjunctivity

A monoid M is said to be surjunctive if every injective cellular automaton with finite alphabet over M is surjective. We show that monoid algebras of surjunctive monoids are stably finite. In other words, given any field K and any surjunctive monoid M, every one-sided invertible square matrix with entries in the monoid algebra K[M] is two-sided invertible. Our proof uses first-order model theory.