  In this paper, a virus optimization algorithm, which is one of the
metaheuristic optimization technique, is employed for the first time to the
problem of finding extremal binary self-dual codes. We present a number of
generator matrices of the form $[I_{36} \ | \ \tau_3(v)],$ where $I_{36}$ is
the $36 \times 36$ identity matrix, $v$ is an element in the group matrix ring
$M_3(\mathbb{F}_2)G$ and $G$ is a finite group of order 12, which we then
employ together with the the virus optimization algorithm and the genetic
algorithm to search for extremal binary self-dual codes of length 72. We obtain
that the virus optimization algorithm finds more extremal binary self-dual
codes than the genetic algorithm. Moreover, by employing the above mentioned
constructions together with the virus optimization algorithm, we are able to
obtain 39 Type I and 19 Type II codes of length 72, with parameters in their
weight enumerators that were not known in the literature before.
