I have never read of printing in agar as primari substance ,maybe because the extruder temperature could affect the agar composition . If you could reach the adecuate temperature to extrude it semi solid could work. I would be very interesting to know if was succesful your work. Good luck sound interesting
I can imagine that it would be possible in the DLP or SLA process, if the photoinitiator is adapted to agar. But without a photoinitiator it will not be possible.