The Red Sable brushes will not survive concentrated acid of any type. The acid will degrade the hairs in the brush, will dissolve the glue holding the hairs in the hilt, and will corrode the soft aluminum shaft of the brush. All these are failure modes.

An alternative strategy is to melt a 1 mm ball onto the end of a glass capillary and use this to apply your lipids to the hole and to form your membranes. As you know, glass will tolerate almost any cleaning procedure you care to apply and can even be sterilized if needed. Just be sure completely seal the end of the glass rod when you melt the tip.